0000000000034575

AUTHOR

P. Gütlich

showing 45 related works from this author

Ni61Mössbauer study of the hyperfine magnetic field near the Ni surface

1987

$^{61}\mathrm{Ni}$ M\"ossbauer measurements have been performed at 4.2 K on spherical Ni particles covered with a protective layer of SiO, with average diameter of 500 and 50 \AA{}. The hyperfine magnetic field at $^{61}\mathrm{Ni}$ nuclei for 500-\AA{} particles has been found to be 78.3(4) kOe, compared with the field for Ni foil of 75.0(2) kOe. The small difference is due to the demagnetization and dipolar fields in 500-\AA{} particles. The spectrum of 50-\AA{} particles has a surface component with the corresponding value of the hyperfine magnetic field of 40.3(5.4) kOe. This strongly indicates that, in accordance with recent theoretical studies, there is a decrease of the hyperfine mag…

Materials scienceMössbauer effectField (physics)Condensed matter physicsDemagnetizing fieldchemistry.chemical_elementMagnetic fieldCondensed Matter::Materials ScienceDipoleNickelchemistryMössbauer spectroscopyAtomic physicsHyperfine structurePhysical Review B
researchProduct

Light-induced formation of metastable high-spin states in [Fe(mtz)6](CiO4)2

1988

[Fe(mtz)6](CiO4)2 (mtz=1-methyltetrazole) is a spin crossover compound with two different iron(II) lattice sites. Only one of them (lattice site A) shows thermally induced high spin (HS) ⇌ low spin (LS) spin transition. The LIESST effect (Light-Induced Excited Spin State Trapping) can be observed below 50 K. Complex molecules in B-sites remain in HS state at all temperatures. At ∼ 20 K irradiation with red light causes a partial conversion to another HS species, HS(C), with also practically infinite lifetime.

Nuclear and High Energy PhysicsSpin statesChemistrySpin transitionCondensed Matter PhysicsAtomic and Molecular Physics and OpticsLIESSTCrystallographySpin crossoverMetastabilityExcited stateMoleculeIrradiationPhysical and Theoretical ChemistryAtomic physicsHyperfine Interactions
researchProduct

57Fe Mössbauer spectroscopy predicts superstructure for K0.08[Cu(II)(N,N'app)Cl]2[Fe(III)(CN)6].0.92H3O.3H2O.

2007

The compound [Cu(N,N'app)Cl](2)[Fe(CN)(6)].xH(2)O, with N,N'app being bis(N,N'-3-aminopropylpiperazine), was prepared and its structure determined by single crystal X-ray analysis, confirming a ratio of two copper complexes to one iron complex; (57)Fe Mössbauer spectra showed three quadrupole doublets typical of iron(iii) low spin species which call for the presence of a superstructure.

Metals and Alloyschemistry.chemical_elementGeneral ChemistryCopperCatalysisSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsCrystallographyNuclear magnetic resonancechemistryQuadrupoleMössbauer spectroscopyMaterials ChemistryCeramics and CompositesIron complexMossbauer spectraSingle crystalSuperstructure (condensed matter)Chemical communications (Cambridge, England)
researchProduct

Determination of the Absolute Density of Fe3+ and Ni2+ Ions in Langmuir-Blodgett Films

1996

By means of the Langmuir–Blodgett (LB) technique, mono- and multilayers of Ni2+ and Fe3+ containing fatty acid salts are transferred onto silicon wafers. After thermal treatment, oxidic layers can be produced. The absolute amounts of Fe3+ and Ni2+ ions per monolayer of LB film were measured and calculated by three different methods. In the case of nickel, the amount expected from theory and preparation conditions was obtained experimentally. In contrast, about twice the number of Fe3+ ions as expected is transferred. An explanation can be given by the presence of hydroxide groups bound to iron. The mean film thickness of the oxidic layers after thermal treatment was estimated where the thic…

inorganic chemicalsX-rayAnalytical chemistrychemistry.chemical_elementSurfaces and InterfacesGeneral ChemistryThermal treatmentCondensed Matter PhysicsLangmuir–Blodgett filmSurfaces Coatings and FilmsIonchemistry.chemical_compoundNickelchemistryMonolayerMaterials ChemistryHydroxideStearic acidSurface and Interface Analysis
researchProduct

Pressure-induced hysteresis in the high spin \leftrightarrow low spin transition in bis(2,4-bis(pyridin-2-yl)thiazole) iron(II) tetrafluoroborate

2008

Studies of the spin transition behavior of the mononuclear compound [Fe(pythiaz)2](BF4)2 have been carried out under hydrostatic pressures up to 9.13 kbar in the 5–300 K temperature range. Under ambient pressure this compound exhibits an approximately half-step (incomplete) HS ↔ LS transition with T1/2 = 146 K without any thermal hysteresis. At pressures up to 4.5 kbar the behavior remains similar but with an upward displacement of T1/2 and a slight decrease in the residual high spin fraction at low T . Application of higher pressures resulted in an almost complete two-step spin transition with several unusual pressure effects. Along with the expected pressure dependence of T1/2 the surpris…

TetrafluoroborateCondensed matter physicsSpin transitionAtmospheric temperature rangeCondensed Matter Physicschemistry.chemical_compoundCrystallographyHysteresischemistryStructural changeGeneral Materials ScienceThiazoleAmbient pressureSpin-½Journal of Physics: Condensed Matter
researchProduct

Magnetic properties of quasi-2D antiferromagnet {N(n-C5H11)4[MnIIFeIII(ox)3]}∞ below Néel temperature: revisited

2004

Abstract Magnetic measurements of {N(n-C 5 H 11 ) 4 [Mn II Fe III (ox) 3 ]} ∞ were carried out in the 5–300 K temperature range under different applied magnetic fields up to 50 kOe with zero-field-cooled (ZFC) and field-cooled (FC) modes. The FC and ZFC χ ( T ) plots exhibited a significantly large bifurcation below the transition temperature, which was traceable even at 50 kOe of applied magnetic field. The bifurcation temperature was found to be magnetic field dependent for the lower range of magnetic fields, which can be represented by a polynomial of magnetic field. The observed magnetic transition temperature of this compound was in good agreement with the earlier reported results. The…

MagnetizationMaterials scienceField (physics)Condensed matter physicsTransition temperatureAntiferromagnetismAtmospheric temperature rangeCondensed Matter PhysicsNéel temperatureMagnetic susceptibilityElectronic Optical and Magnetic MaterialsMagnetic fieldJournal of Magnetism and Magnetic Materials
researchProduct

Time integral and time differential Mössbauer measurements on [57Co/Mn(bipy)3](PF6)2

1994

The Mossbauer emission spectra of nucleogenic iron(II) complexes with a low spin (LS) ground state show two metastable iron(II) high spin (HS) states at low temperatures. In order to identify these metastable HS states, the compound [57Co/Mn(bipyridine)3](PF6)2 has been studied by time differential Mossbauer emission spectroscopy (TDMES) and optical lifetime measurements of excited electronic states in the corresponding Fe-doped Mn compound. The lifetime of one of the HS states of the nucleogenic iron(II) determined by TDMES has been measured to be the same as the lifetime of the laser-excited iron(II) electronic state.

Nuclear and High Energy PhysicsAstrophysics::High Energy Astrophysical PhenomenaAnalytical chemistryComputer Science::Computational GeometryCondensed Matter PhysicsAtomic and Molecular Physics and OpticsBipyridinechemistry.chemical_compoundchemistryNucleogenicMetastabilityMössbauer spectroscopyCondensed Matter::Strongly Correlated ElectronsEmission spectrumPhysical and Theoretical ChemistryGround stateSpectroscopySpin (physics)Hyperfine Interactions
researchProduct

Surface Analysis in Archaeology Using the Miniaturized Mössbauer Spectrometer MIMOS II

2003

A miniaturized Mossbauer spectrometer (MIMOS II) which was designed and constructed for extraterrestrial applications, such as iron-containing rock and soil analysis on the planet Mars, has been employed to investigate the iron-containing constituents in the paintings of a Lekythos Greek vase. Greek pottery is commonly painted with black figures. The Mossbauer backscattering spectra recorded with MIMOS II at room temperature show that the hand-painted black figures contain hematite.

Nuclear and High Energy PhysicsSpectrometerChemistryvisual_artMössbauer spectroscopyvisual_art.visual_art_mediumMineralogyPotteryPhysical and Theoretical ChemistryPlanet MarsHematiteCondensed Matter PhysicsAtomic and Molecular Physics and OpticsHyperfine Interactions
researchProduct

Magneto-structural correlations in self-assembled spin-transition nano-architectures of the [][2×2]-grid-type

2004

Abstract The magnetism of a series of tetranuclear complexes of the [ Fe II 4 L 4 ]( BF 4 ) 8 [2×2] -grid-type was investigated, revealing the occurrence of spin-transition (ST) behavior within this class of compounds. The phenomenon depends directly on the nature of the substituent R1 of the ligand L . All FeII ions in compounds with R1 substituents favoring strong ligand fields ( R 1 = H ; OH ) remain completely in the diamagnetic low-spin state. Only the complex bearing R1=Ph exhibits thermally induced ST behavior.

Materials scienceMagnetismLigandSpin transitionSupramolecular chemistrySubstituentCondensed Matter PhysicsMagnetic susceptibilityElectronic Optical and Magnetic MaterialsIonCrystallographychemistry.chemical_compoundchemistryDiamagnetismJournal of Magnetism and Magnetic Materials
researchProduct

Structural phase transition to disorder low-temperature phase in [Fe(ptz)6](BF4)2 spin-crossover compounds.

2012

In the spin-crossover compound [Fe(ptz)6](BF4)2 (where ptz=1-n-propyltetrazole) six different phases are observed. When a single crystal is slowly cooled from high temperatures to those below 125 K, the reflections broaden into diffuse maxima and split into two maxima along the c* direction [Kusz, Gütlich & Spiering (2004). Top. Curr. Chem. 234, 129–153]. As both maxima are broad along the c* direction, the short-range order exists only along the c direction and in the ab plane the structure remains long-range ordered. In this disordered phase additional satellite reflections appear. Upon heating above 135 K, the diffuse maxima return to their previous shape and this process is complete…

CrystallographyPhase transitionPolyhedronCondensed matter physicsSpin crossoverChemistryLattice (order)General MedicineMaximaCrystal twinningSingle crystalGeneral Biochemistry Genetics and Molecular BiologyIonActa crystallographica. Section B, Structural science
researchProduct

Pressure Effect on Spin Crossover in [Fe(phen)2(NCS)2] and [CrI2(depe)2]

2004

In the present article, we discuss the results of investigations of the influence of hydrostatic pressure (up to 1.2 GPa) on the spin transition behavior in [Fe(phen)2(NCS)2] polymorph II and [CrI2(depe)2]. It is demonstrated that pressure effect studies are very helpful in elucidating the mechanism of cooperative dynamic electronic structure phenomena accompanied by significant volume changes. Application of hydrostatic pressure serves as a tool for modifying the ligand field strength in a controlled manner.

Condensed matter physicsSpin crossoverChemistryHydrostatic pressureSpectrochemical seriesMaterials ChemistrySpin transitionPhysical chemistryElectronic structurePhysical and Theoretical ChemistrySurfaces Coatings and FilmsThe Journal of Physical Chemistry B
researchProduct

57Fe,61Ni, and121Sb M�ssbauer study of oxidic spinel ferrites CoxNi5/3?xFeSb1/3O4

1987

Antimony substituted nickel ferrites Co x Ni5/3−xFeSb1/3O4 withx=0,1/3,1,4/3, and 5/3 were prepared by the common ceramic technique, and the single-phase structure was confirmed by x-ray powder diffraction.57Fe Mossbauer spectra were recorded at 4.2 K with and without an applied magnetic fieldHlong=60 kOe in order to determine the cation distribution and the spin structure. Utilizing the cation distributions and the Yafet-Kittel spin structures for B-site Fe3+ ions, derived from Mossbauer experiments the calculated magnetic moments are in excellent agreement with the experimental values at 4.2 K. The existence of Ni2+ ions in crystallographic A-sites was confirmed by61Ni Mossbauer spectrosc…

Physics and Astronomy (miscellaneous)Magnetic momentMössbauer effectChemistryGeneral EngineeringIonic bondingGeneral ChemistryIonMagnetizationNuclear magnetic resonanceMössbauer spectroscopyPhysical chemistryGeneral Materials ScienceSpin (physics)Hyperfine structureApplied Physics A Solids and Surfaces
researchProduct

Lamb-Mössbauer factor in the spin crossover compound Fe(tpa)(NCS)2

1994

The Lamb-Mossbauer factor in spin crossover compounds has been the subject of controversial discussions in the literature. For several compounds, a significantly larger Lamb-Mossbauer factor for the complex molecules in the low-spin (fls) than in the high-spin (fhs) state has been reported, while for compounds studied in our laboratory such differences could not be observed. We prepared the compound Fe(tpa)(NCS)2, thef factors of which were reported to be very different. We could not prove thef factors of this compound to be different. The implications of a different structural phase of compound prepared by us are discussed.

Nuclear and High Energy PhysicsCrystallographyStructural phaseChemistryStereochemistrySpin crossoverMoleculeLamb–Mössbauer factorPhysical and Theoretical ChemistryCondensed Matter PhysicsAtomic and Molecular Physics and OpticsHyperfine Interactions
researchProduct

Hysteresis in the spin transition regime of [Fe(NH2trz)3](NO3)2 as probed by ZF-μSR

2006

The thermal spin transition which occurs in the polymeric chain compound [Fe(NH(2)trz)(3)](NO3)(2) above room temperature has been investigated by zero-field muon spin relaxation (mu SR) (similar to 8-402 K). The depolarization curves are best described by a Lorentzian and a Gaussian line that represent fast and slow components respectively. The spin transition is associated with a hysteresis loop of width Delta T = 34 K (T-1/2(up arrow) = 346 K and T-1/2(down arrow) = 312 K) that has been delineated by the temperature variation of the initial asymmetry parameter. Comparison of zero-field and transverse field (20 Oe) mu SR measurements shows that diamagnetic muon species occur over the enti…

ParamagnetismMaterials scienceMuonCondensed matter physicsSpin crossoverRelaxation (NMR)MuoniumSpin transitionElectrical and Electronic EngineeringAtmospheric temperature rangeMuon spin spectroscopyCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsPhysica B: Condensed Matter
researchProduct

New time-differential Mössbauer emission measurements on the high-spin→low-spin relaxation in [57Co/Co(phen)3](ClO4)2

1990

Using our new spectrometer for time-differential Mossbauer emission spectroscopy we reinvestigated the high-spin→low-spin relaxation following the57Co(EC)57Fe process in [57Co/Co(phen)3](ClO4)2 (phen=1,10-phenanthroline). In contrast to former investigations we found a temperature dependent initial population less than 1 for the metastable high-spin states. The results and the data evaluation method are presented.

Nuclear and High Energy Physicseducation.field_of_studySpectrometerChemistryRelaxation (NMR)PopulationAnalytical chemistryCondensed Matter PhysicsAtomic and Molecular Physics and OpticsMetastabilityMössbauer spectroscopyEmission spectrumPhysical and Theoretical ChemistrySpectroscopySpin (physics)educationHyperfine Interactions
researchProduct

The debye-waller factor in spincrossover molecular crystals: a mössbauer study on [FexZn1−x(ptz)6](BF4)2

1995

In a first approximation the Debye-Waller factor (DWF) of molecular crystals is factorized into a molecular and a lattice part:f=f m f l. In the case of spincrossover compounds there is the unique possibility to measure differences of both parts in the two spin states by switching the spin states with the LIESST effect. Measurements of the DWF depending on temperature, γ-ray direction and spin state were performed with57Fe-Mossbauer spectroscopy on three single crystals (R¯3) of the spincrossover system [FexZn1−x(ptz)6](BF4)2 (ptz=1-propyltetrazole), a concentrated sample withx=1 and diluted ones withx=0.30 andx=0.005. The DWF decreases from 10 to 300 K by a factor of ∼ 100 and its anisotro…

Nuclear and High Energy PhysicsOptical latticeCondensed matter physicsSpin statesChemistryAnalytical chemistryCondensed Matter PhysicsAtomic and Molecular Physics and OpticsLIESSTLattice (order)Mössbauer spectroscopyMoleculePhysical and Theoretical ChemistryDebye–Waller factorSpectroscopyHyperfine Interactions
researchProduct

Spin crossover in hexakis(1-(2-chloroethyl)-tetrazole)iron(II) complexes; synthesis and magnetic properties

2002

Abstract The spin-crossover complexes [Fe(teec)6](X)2 (with teec=1-(2-chloroethyl)-tetrazole and X=BF4, ClO4, PF6) possess two iron(II) sites each having a different spin-crossover behaviour. The magnetic behaviour of the complexes obtained by slow crystallisation differs strongly from those obtained by precipitation. This difference results in either a spin crossover of 50% (X=ClO4, crystalline), two gradual steps (X=BF4, PF6), or two steps, of which one is gradual and the other having a thermal hysteresis (X=ClO4 precipitated). Both 57Fe Mossbauer spectroscopy and magnetic susceptibility measurements have been recorded as a function of T. The crystal structure of [Fe(teec)6](BF4)2 has bee…

Ligand field theorySpin transitionCrystal structureMagnetic susceptibilitylaw.inventionInorganic Chemistrychemistry.chemical_compoundCrystallographychemistrySpin crossoverlawMössbauer spectroscopyMaterials ChemistryTetrazolePhysical and Theoretical ChemistryCrystallizationInorganica Chimica Acta
researchProduct

Thermal- and light-induced spin crossover in novel 2D Fe(II) metalorganic frameworks {Fe(4-PhPy)(2)[M(II)(CN)(x)](y)}.sH(2)O: spectroscopic, structur…

2009

Five novel two-dimensional coordination polymers {Fe(4PhPy)(2)[M(II)(CN)(4)]}.sH(2)O (4PhyPy = 4-phenylpyridine; 1: M(II) = Pd, s = 0; 2: M(II) = Ni, s = 0; 3: M(II) = Pt, s = 1) and {Fe(4PhPy)(2)[M(I)(CN)(2)](2)}.sH(2)O (4: M(I) = Ag, s = 1; 5: M(I) = Au, s = 0.5) exhibiting spin-crossover properties have been synthesized. They were characterized at various temperatures using X-ray absorption spectroscopy (XAS), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and magnetic susceptibility measurements. The occurrence of a cooperative thermal spin transition detected by the magnetic method is located at critical temperatures T(c)( downward arrow)/T(c)( upward arrow) …

chemistry.chemical_classification010405 organic chemistryChemistryPolymer010402 general chemistry01 natural sciences0104 chemical sciencesInorganic ChemistryCrystallographyNuclear magnetic resonanceSpin crossoverThermalLight inducedPhysical and Theoretical ChemistryInorganic chemistry
researchProduct

Debye-Waller factor in the spin crossover complex Fe(ppi)2(NCS)2

1997

Abstract Mossbauer spectroscopy and magnetic susceptibility measurements for the complex Fe(ppi) 2 (NCS) 2 in the temperature range 11–300 K indicate that the spin transition of this compound is incomplete until 11 K. The similar Debye-Waller factors in high spin (HS) and low spin (LS) states is shown by the comparison of the HS fractions from the two different methods. The Debye temperature of the compound was calculated from the defined Debye-Waller factors obtained from Mossbauer measurement at each experimental temperature and was found to depend on the temperature as well as on the HS fraction. The modification of the Debye-Waller factors in the HS and LS states for the HS fraction fro…

Condensed matter physicsMössbauer effectChemistryAnalytical chemistrySpin transitionAtmospheric temperature rangeCondensed Matter PhysicsMagnetic susceptibilitysymbols.namesakeSpin crossoversymbolsGeneral Materials ScienceDebye–Waller factorSpin (physics)Debye modelMaterials Chemistry and Physics
researchProduct

On-line Mössbauer measurements at low temperatures of 83mKr implanted into Al

1978

Abstract A vacuum ion implantation chamber housing a helium flow cryostat and a Mossbauer transducer has been constructed and coupled directly to an ion separator for low temperature implantation and on-line Mossbauer measurements. 83m Kr, produced by thermal neutron activation of enriched 82 Kr gas, has been implanted into Al foils in the temperature range 15–300 K. Annealing effects and the temperature dependence of the Lamb-Mossbauer factor have been studied by Mossbauer measurements (at 15–35 K) using the implanted Al targets as sources and Kr/hydrochinone as absorber.

CryostatMaterials scienceAnnealing (metallurgy)Analytical chemistrychemistry.chemical_elementGeneral MedicineAtmospheric temperature rangeNeutron temperatureIonIon implantationNuclear magnetic resonancechemistryMössbauer spectroscopyHeliumNuclear Instruments and Methods
researchProduct

57Fe and119Sn Mössbauer investigations on some substituted barium hexaferrites

1994

57Fe and119Sn Mossbauer measurements have been carried out on powder samples of three differently substituted M-type barium hexaferrites. By57Fe Mossbauer measurements in an external magnetic field applied parallel to the γ-ray direction, we found a canted spin structure for all samples. Furthermore, we detected a strong preference of the Sn4+ ions for the 4f2 sites. From57Fe Mossbauer measurements aboveT N, we conclude that the substitution does not influence the 2b sites. The analysis of the magnetically split119Sn Mossbauer spectra at room temperature in the case of the Co-Sn and Zn-Sn substituted samples shows a strong difference between the two. The spectra were interpreted due to the …

Nuclear and High Energy PhysicsCondensed matter physicschemistry.chemical_elementBariumSpin structureCondensed Matter PhysicsAtomic and Molecular Physics and OpticsSpectral lineMagnetic fieldIonCrystallographychemistryMössbauer spectroscopyMossbauer spectraPhysical and Theoretical ChemistryHyperfine Interactions
researchProduct

Investigation of ultrathin iron and iron/nickel layers prepared from Langmuir-Blodgett films

1996

Oxidic and metallic iron and iron/nickel multilayers, formed after thermal and chemical treatment of Langmuir-Blodgett films, were investigated. Reduced iron-stearate multilayers were compared with evaporated films concerning their phase composition and their lateral homogeneity. The sequence of metallic and oxidic iron in the films after reduction was determined. Oxidic iron/nickel mixed layers can be prepared from Langmuir-Blodgett films, in which a magnetically non-ordered Fe3+ phase exhibiting a distribution of the quadrupole splitting is observed. After reduction of such layers, two metallic iron phases appear dependent on the nickel concentration. The hyperfine field distribution of t…

Mössbauer effectChemistryAnalytical chemistrychemistry.chemical_elementGeneral ChemistryQuadrupole splittingLangmuir–Blodgett filmMetalNickelX-ray photoelectron spectroscopyTransition metalvisual_artvisual_art.visual_art_mediumGeneral Materials ScienceThin filmApplied Physics A Materials Science & Processing
researchProduct

61Ni Mössbauer study of the surface hyperfine magnetic field in nickel

1988

61Ni Mossbauer measurements have been performed at 4.2 K on spherical Ni particles with an average diameter of 100 and 30 A, covered with a protective layer of SiO. Their spectra contain a surface component with a significantly reduced hyperfine magnetic field as compared with the field in the bulk. This result confirms recent theoretical predictions.

Surface (mathematics)Nuclear and High Energy PhysicsField (physics)Average diameterCondensed matter physicsChemistryAnalytical chemistrychemistry.chemical_elementCondensed Matter PhysicsAtomic and Molecular Physics and OpticsSpectral lineMagnetic fieldNickelMössbauer spectroscopyPhysical and Theoretical ChemistryHyperfine structureHyperfine Interactions
researchProduct

K2MIII2(MVIO4)(PO4)2 (MIII = Fe, Sc; MVI = Mo, W), Novel Members of the Lagbeinite-Related Family: Synthesis, Structure, and Magnetic Properties

2012

The possibility of PO(4)(3-) for MoO(4)(2-) partial substitution in the langbeinite framework has been studied by exploration of the K-Fe(Sc)-Mo(W)-P-O systems using the high-temperature solution method. It was shown that 1/3PO(4)(3-) for MoO(4)(2-) substitution leads to formation of three novel compounds K(2)Fe(MoO(4))(PO(4))(2), K(2)Sc(MoO(4))(PO(4))(2), and K(2)Sc(WO(4))(PO(4))(2) with slightly increased lattice parameters and significant distortion of the anion tetrahedra without structure changes. In contrast, the antiferromagnetic structure is modified by substitution in the low-temperature region. The structural peculiarities are discussed in light of bond-valence sums calculations.

Inorganic ChemistryCrystallographyLangbeiniteChemistryLattice (order)AntiferromagnetismPhysical and Theoretical ChemistryPartial substitutionIonInorganic Chemistry
researchProduct

Low noise scintillation detectors with a P-47 thin layer screen for electrons of several keV

1994

Abstract The applicability of a low-noise scintillation detector (ScD) for the registration of electrons of several keV energy has been studied employing photomultipliers (PM) of different types and sizes. With the application of a sedimented P-47 scintillation screen, the values of the low-energy sensitivity limit and those of the light conversion coefficient were determined as about 2.7–4.7 keV and 2.8–6.6 photoelectrons/keV, respectively, for the set of PM's (Philips-Valvo XP 2020, Philips-Valvo XP 2052, Philips-Valvo XP 2972, EMI 9124a) studied. It is concluded that such scintillation detectors might be used advantageously as electron counters in the range of E > 5 keV. Applications bel…

PhysicsNuclear and High Energy PhysicsPhotomultiplierScintillationRange (particle radiation)Physics::Instrumentation and Detectorsbusiness.industryDetectorElectronScintillatorPhotoelectric effectKinetic energyOpticsbusinessInstrumentationNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
researchProduct

Mössbauer effect study of the electronic ground state of iron(II) in [57FexM1−x(bipy)3](ClO4)2 (M = Mn, Ni, Zn) and [57FexM1−x(phen)3](ClO4)2 (M = Ni…

1980

Earlier work in our laboratory on the effect of metal dilution on the 5T2(Oh ⇌ 1A1(Oh) equilibrium in polycrystalline spin crossover systems of iron(II) has shown that the relative stability of the high spin state, 5T2(Oh), at a given temperature, increases markedly with decreasing iron concentration. These results have initiated the present work. Using 57Fe Mossbauer spectroscopy, we have investigated the electronic ground state of iron(II) in the highly diluted solid solutions [FexM1−xL3] with L = bipy, M = Mn, Ni, Zn, x ≲ 0.005 and L = phen, M = Ni, Zn, x ≲ 0.005. Although the critical field potential (Vc) of the pure iron complexes, which are known to be low spin, is reported to be not …

Ionic radiusSpin statesChemistryInorganic chemistryAnalytical chemistryQuadrupole splittingInorganic ChemistryMetalSpin crossovervisual_artMössbauer spectroscopyMaterials Chemistryvisual_art.visual_art_mediumPhysical and Theoretical ChemistryGround stateSolid solutionInorganica Chimica Acta
researchProduct

Polarized neutron diffraction and Mössbauer spectral study of short-range magnetic correlations in the ferrimagnetic layered compounds(PPh4)[FeIIFeII…

2002

Short-range antiferromagnetic correlations have been studied in the layered compounds (PPh 4 ) [Fe I I Fe I I I (ox) 3 ] and (NBu 4 ) [Fe I I Fe I I I (ox) 3 ] by neutron polarization analysis and Mossbauer spectroscopy. Polarized neutron diffraction profiles obtained between 2 and 50 K on (d 2 0 -PPh 4 ) [Fe I I Fe I I I (ox) 3 ] show no magnetic Bragg scattering; the lack of such scattering indicates the absence of long-range magnetic order. However, a broad asymmetric feature observed at a Q of ca. 0.8 A - 1 is attributed to two-dimensional short-range magnetic correlations, which are described by a Warren function. The correlation length is ca. 50 A between 2 and 30 K and then decreases…

ParamagnetismCrystallographyMaterials scienceCondensed matter physicsMössbauer effectFerrimagnetismMössbauer spectroscopyNeutron diffractionAntiferromagnetismNeutron scatteringNéel temperaturePhysical Review B
researchProduct

Spin crossover in solid solution

1980

Abstract The temperature dependent high spin (HS) ⇌ low spin (LS) transition, otherwise called spin crossover, has been well established for many first-row transition metal complexes, particularly for complexes of iron(II) [1]. The phenomenon has been observed mostly in the crystalline state, but also in solution. The spin crossover characteristics have been found to depend on various chemical influences, such as ligand substitution, the nature of the non-coordinating anion and the crystallizing solvent. It has been shown by 57Fe Mossbauer spectroscopy that the spin crossover behaviour in the solid solutions of [FexZn1−x(2-pic)3] Cl2·EtOH (2-pic = 2-picolylamine) is also susceptible to meta…

Mössbauer effectSpin statesCondensed matter physicsChemistryEnthalpyThermodynamicsInorganic ChemistryTransition metalSpin crossoverMolecular vibrationMössbauer spectroscopyMaterials ChemistryPhysical and Theoretical ChemistrySolid solutionInorganica Chimica Acta
researchProduct

Mössbauer Spectral Study of Two Layered Honeycomb Molecular Magnets: PPh4FeIIFeIII(ox)3 and NBu4FeIIFeIII(ox)3

2002

The Mossbauer spectra of the layer ferrimagnets PPh4FeIIFeIII(ox)3 and NBu4FeIIFeIII(ox)3 have been measured between 1.9 and 315 K. The paramagnetic spectra exhibit both high-spin iron(II) and iron(III) doublets. The iron(II) quadrupole splittings are negative and decrease substantially upon cooling as a result of a low-symmetry crystal field splitting. In contrast, the iron(III) splittings are small, positive, and virtually independent of temperature. The respective magnetic ordering temperatures of 30 and 42.5 K agree well with the phase observed by bulk magnetometry and the magnetic sextets yield hyperfine fields of ca. 60 kOe for iron(II) and 540 kOe for iron(III). The unusually low iro…

ParamagnetismDipoleMaterials scienceCrystal field theoryMössbauer spectroscopyQuadrupoleAnalytical chemistryQuadrupole splittingHyperfine structureSpectral line
researchProduct

Metal-to-metal electron transfer and magnetic interactions in a mixed-valence Prussian Blue analogue

2006

Abstract In search of a new Prussian Blue analogue exhibiting fascinating magnetic properties, potassium manganese hexacyanoferrate, K 0.2 Mn 0 . 66 II Mn 1.44 III [ Fe 0.2 II Fe 0.8 III ( CN ) 6 ] O 0.66 ( CH 3 COO ) 1.32 ] , 7.6H2O, has been synthesized. This compound undergoes a paramagnetic to ferrimagnetic transition at 10 K. Temperature and magnetic field-dependent magnetization studies of this compound have revealed different spin alignments below and above 3 K. The nature of possible magnetic interactions between the nearest neighbor magnetic centers has been discussed in order to explore the origin of the observed magnetic interactions. Mossbauer spectroscopic study at different te…

Prussian blueMaterials scienceCondensed matter physicsMagnetismCondensed Matter PhysicsElectronic Optical and Magnetic Materialschemistry.chemical_compoundCrystallographyElectron transferParamagnetismMagnetizationchemistryFerrimagnetismSpin crossoverFerrocyanideJournal of Magnetism and Magnetic Materials
researchProduct

Optimization of a conversion electron Mössbauer spectroscopy gas flow He/CH4 proportional counter

1992

A new detector for CEMS has been built and optimized with respect to the statistical quality of spectra obtained. The optimization has been performed by measuring Mosbauer and pulse height spectra at in- and off-resonance. Single channel analyzer settings were calculated by a new optimization routine. A comparison of different detector designs has been performed using the statistical utility rate of spectra obtained from a stainless steel foil. A procedure for determining optimal operating parameters for ICEMS gas flow proportional counters is proposed.

Nuclear and High Energy PhysicsSpectrum analyzerMaterials sciencePhysics::Instrumentation and DetectorsDetectorFlow (psychology)Analytical chemistryProportional counterCondensed Matter PhysicsAtomic and Molecular Physics and OpticsSpectral lineConversion electron mössbauer spectroscopyPhysical and Theoretical ChemistryFOIL methodPulse heightHyperfine Interactions
researchProduct

conversion electron Mössbauer study of low carbon steel polarized in aqueous sulfate solution containing sulfite in low concentration

1992

The passivation of low carbon steel was studied in aqueous solution of 0.5 M Na2SO4+0.001 M NaHSO3 at pH=3.5 and 6.5. The found major components at pH-3.5 were: γ-FeOOH and Fe3C, and also FeSO4.H2O could be identified on the surface of the low carbon steel as a minor component. At pH-6.5, the passive film contained only amorphous iron(III)-oxide or oxyhydroxide.

Nuclear and High Energy PhysicsAqueous solutionMaterials sciencePassivationCarbon steelInorganic chemistryElectronengineering.materialCondensed Matter PhysicsAtomic and Molecular Physics and OpticsAmorphous solidchemistry.chemical_compoundSulfitechemistryMössbauer spectroscopyengineeringPhysical and Theoretical ChemistrySulfateHyperfine Interactions
researchProduct

Layer formation on silicon steel by processing in H2/H2O at elevated temperatures

1992

Silicon steel (Fe-3wt%Si), as used for transformers and generators, has been annealed in wet hydrogen at elevated temperatures. The composition, sequence, and thicknesses of the layers found by conversion electron Mossbauer spectroscopy (CEMS) and Auger electron spectroscopy (AES) depth profiling for a 10 minutes anneal in different atmospheres are reported. In the range from 500°C to 720°C we observed carbide formation, indicating that the decarburization is hindered. Above 800°C, the layers consist of fayalite or of fayalite and iron oxides, depending on the oxygen potentialaO. At 843°C, the onset of iron oxide formation was found ataO=0.33.

Nuclear and High Energy PhysicsAuger electron spectroscopyMaterials scienceDecarburizationHydrogenMetallurgyIron oxidechemistry.chemical_elementengineering.materialCondensed Matter PhysicsAtomic and Molecular Physics and OpticsCarbidechemistry.chemical_compoundchemistryConversion electron mössbauer spectroscopyengineeringFayalitePhysical and Theoretical ChemistryElectrical steelHyperfine Interactions
researchProduct

Synchrotron powder-diffraction study of the spin transition compound [Fe(bpp)2](NCS)2·2H2O and soft X-ray-induced structural phase conversion

2008

Abstract We have studied the high spin and low spin structural phases of the two-step spin transition compound [Fe(bpp) 2 ](NCS) 2 ·2H 2 O (bpp: 2,6-bis(pyrazol-3-yl)pyridine) of different sample history with X-ray synchrotron ( λ  ∼ 0.32 A) powder diffraction at different temperatures as well as with usual X-ray ( λ  ∼ 1.54 A) powder diffraction at room temperature by performing rapid repeated scans at regular intervals of time. A structural phase transition occurs only during the first step of the spin transition. Time dependent interconversions of the two crystallographic phases have been observed at room temperature for this material. The results indicate that a soft X-ray (Cu-K α )-ind…

SAMPLE historyOrganic ChemistrySpin transitionSynchrotronAnalytical Chemistrylaw.inventionInorganic ChemistryCrystallographychemistry.chemical_compoundMagazineStructural changechemistrylawPyridineSpin (physics)SpectroscopyPowder diffractionJournal of Molecular Structure
researchProduct

Poster contributions

1989

Nuclear and High Energy PhysicsMaterials sciencePhysical and Theoretical ChemistryCondensed Matter PhysicsAtomic and Molecular Physics and OpticsHyperfine Interactions
researchProduct

Dynamics of BF 4 - anion reorientation in the spin-crossover compound [Fe(1-n-propyl-1H-tetrazole) 6 ](BF 4 ) 2 and in its Zn II analogue

1999

19 F and 11 B spin-lattice relaxation times were measured in [ Zn ( ptz ) 6 ] ( BF 4 ) 2 and in the spin-crossover compound [ Fe ( ptz ) 6 ] ( BF 4 ) 2 . For both compounds BF 4 - anion reorientation is active above 50 K. For [ Zn ( ptz ) 6 ] ( BF 4 ) 2 , the anion-reorientation dynamics is different in the temperature regions of 50-90 K, 90-120 K, and above 150 K; between 120 and 150 K it changes rapidly reflecting a structural change. In [ Fe ( ptz ) 6 ] ( BF 4 ) 2 the mechanism for the paramagnetic relaxation involving the 19 F nuclei is found to be of the diffusion-limited type according to the theory of Lowe and Tse. The present results prove that the spin-crossover takes place in a dy…

Lattice dynamicschemistry.chemical_compoundParamagnetismCrystallographyTetrafluoroborateNuclear magnetic resonancechemistrySpin crossoverSpin–lattice relaxationCrystal structure1H-tetrazoleAtomic and Molecular Physics and OpticsIonThe European Physical Journal D - Atomic, Molecular and Optical Physics
researchProduct

Gamma-X-ray coincidence Mössbauer emission spectroscopy on57Co/CoO

1994

The time integral Mossbauer emission spectrum of a57Co/Co1−xO source (x ≈ 10−5) at RT consists of two single Lorentzian lines of an Fe2+ (76%) charge state and an Fe3+ (24%) aliovalent charge state. The spectrum measured by γ-X-ray coincidence spectrpscopy shows the same fraction of the aliovalent charge state, contrary to the expectation derived from the competing acceptor model as successfully applied by Tejada and Parak [1], who could explain the dependence of the formation of aliovalent charge states after the nuclear transformation on the stoichiometric parameterx. The consequences of this unexpected behaviour for the competing acceptor model are discussed.

Nuclear and High Energy PhysicsChemistryX-rayAnalytical chemistryCharge (physics)Condensed Matter PhysicsAcceptorAtomic and Molecular Physics and OpticsCoincidenceMössbauer spectroscopyTime integralEmission spectrumPhysical and Theoretical ChemistryAtomic physicsStoichiometryHyperfine Interactions
researchProduct

Spin Transition Compounds

2001

Materials scienceCondensed matter physicsSpin transition
researchProduct

The effect of energy-dependent detector efficiency in electron spectroscopic methods: XPS, AES and DCEMS

1993

Systematic studies were performed to investigate the distorting effect of the electron energy dependence of the channeltron detector efficiency on the shape of data distributions in electron spectroscopy. In agreement with earlier results for electron energies up to 3 keV, it was found that a virtually energy-independent shape of the electron distribution might be achieved even in a very broad range of electgron energies (up to 15 keV) by appropriate selection of the operational high voltage of a channeltron. However, the efficieny of channeltrons was also found to depend on count rates, indicating one of the principal difficulties in comparing distribution recorded under different experime…

Range (particle radiation)Auger electron spectroscopyMössbauer effectChemistryInstrumentationDetectorSurfaces and InterfacesGeneral ChemistryElectronCondensed Matter PhysicsElectron spectroscopySurfaces Coatings and FilmsX-ray photoelectron spectroscopyMaterials ChemistryAtomic physicsSurface and Interface Analysis
researchProduct

CCDC 273105: Experimental Crystal Structure Determination

2005

Related Article: J.Kusz, D.Schollmeyer, H.Spiering, P.Gütlich|2005|J.Appl.Crystallogr.|38|528|doi:10.1107/S0021889805009891

Space GroupCrystallographyCrystal SystemCrystal Structuretris(2-Picolylamine)-iron(ii) dichloride ethanol solvateCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 273101: Experimental Crystal Structure Determination

2005

Related Article: J.Kusz, D.Schollmeyer, H.Spiering, P.Gütlich|2005|J.Appl.Crystallogr.|38|528|doi:10.1107/S0021889805009891

Space GroupCrystallographyCrystal SystemCrystal Structuretris(2-Picolylamine)-iron(ii) dichloride ethanol solvateCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 273100: Experimental Crystal Structure Determination

2005

Related Article: J.Kusz, D.Schollmeyer, H.Spiering, P.Gütlich|2005|J.Appl.Crystallogr.|38|528|doi:10.1107/S0021889805009891

Space GroupCrystallographyCrystal SystemCrystal Structuretris(2-Picolylamine)-iron(ii) dichloride ethanol solvateCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 273102: Experimental Crystal Structure Determination

2005

Related Article: J.Kusz, D.Schollmeyer, H.Spiering, P.Gütlich|2005|J.Appl.Crystallogr.|38|528|doi:10.1107/S0021889805009891

Space GroupCrystallographyCrystal SystemCrystal Structuretris(2-Picolylamine)-iron(ii) dichloride ethanol solvateCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 273104: Experimental Crystal Structure Determination

2005

Related Article: J.Kusz, D.Schollmeyer, H.Spiering, P.Gütlich|2005|J.Appl.Crystallogr.|38|528|doi:10.1107/S0021889805009891

Space GroupCrystallographyCrystal SystemCrystal Structuretris(2-Picolylamine)-iron(ii) dichloride ethanol solvateCell ParametersExperimental 3D Coordinates
researchProduct

CCDC 273103: Experimental Crystal Structure Determination

2005

Related Article: J.Kusz, D.Schollmeyer, H.Spiering, P.Gütlich|2005|J.Appl.Crystallogr.|38|528|doi:10.1107/S0021889805009891

Space GroupCrystallographyCrystal SystemCrystal Structuretris(2-Picolylamine)-iron(ii) dichloride ethanol solvateCell ParametersExperimental 3D Coordinates
researchProduct