Search results for "Mössbauer effect"

Mossbauer spectroscopic study of the thermal spin crossover in [Fe(II)(isoxazole)(6)](ClO(4))(2)

2008

The (57)Fe Mossbauer spectroscopy of mononuclear [Fe(II)(isoxazole)(6)](ClO(4))(2) has been studied to reveal the thermal spin crossover of Fe(II) between low-spin (S = 0) and high-spin (S = 2) states.Temperature-dependent spin transition curves have been constructed with the least-square fitted data obtained from the Mossbauer spectra measured at various temperatures between 84 and 270 K during a cooling and heating cycle. This compound exhibits an unusual temperature-dependent spin transition behaviour with T(C)(down arrow) = 223 and T(C)(up arrow) = 213 K occurring in the reverse order in comparison to those observed in SQUID observation and many other spin transition compounds. The comp…

Mössbauer Spectroscopic Evidence of Angle-Dependent Intersystem Crossing in LiNbO3:Fe3+

1986

M\"ossbauer emission spectra of LiNb${\mathrm{O}}_{3}$:$^{57}\mathrm{Co}$ single crystals in magnetic fields up to 5 T at 4.2 K show initial populations of the $^{6}A_{1\mathrm{g}}$ Zeeman substates of ${\mathrm{Fe}}^{3+}$ which depend strongly on the angle between the crystallographic $c$ axis and the magnetic field. This is interpreted in terms of a crystal-field effect on excited states which influences the initial populations of the Zeeman sublevels of the $^{6}A_{1\mathrm{g}}$ ground term after the electron-capture decay of $^{57}\mathrm{Co}$. An intersystem crossing process due to orbit-lattice interaction can fairly well explain the angular dependence.

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…

Antimony-121 Mössbauer spectra of organoantimony derivatives containing Sb-Sb bonds

1994

121-Sb Mossbauer data are reported for a number of organoantimony rings and catena-stibanes. These compounds are representative of RSb(Sb)2 and R2SbSb type of coordination, and spectral parameters are compared and discussed in relation to RSbCl2 and R2SbCl systems. Although the trend in isomer shift is similar, the present compounds show slightly less negative isomer shift values together with a remarkable reduction of the quadrupolar coupling constant. A rationalization of the quadrupolar interaction in the above series of compounds appears feasible by using point charge model calculations whose results, in terms of bonding, indicate a large contribution of p-electron density along Sb-Sb b…

MÖSSBAUER EFFECT STUDY ON THE HIGH-SPIN (5T2) ⇌ LOW SPIN (1A1) TRANSITION IN [Fe(2-pic)3]Cl2. DILUTION EFFECT IN [FexZn1-x(2-pic)3] Cl2. EtOH AND CRY…

1976

Stoichiometry of LiNiO2 Studied by Mössbauer Spectroscopy

2002

From the 61Ni and 57Fe Mossbauer spectroscopy data follows the cationic site assignment in Li1−x Ni1+x O2. Our data explain the ferromagnetic properties of this material because of the appearance of Ni2+ (S = 1) among Ni3+ (S = 1/2) in Ni3+O2 hexagonal planes. We have no evidence for the ferromagnetic interaction between the NiO2 layers through the excess Ni2+ ions substituting the Li+ ions. The presence of Ni2+ found in the Ni3+O2 planes explains the absence of the Jahn-Teller distortions probably because of the electronic transfer between the Ni3+ and Ni2+ ions.

Ni participation in the magnetism of Fe-Ni-Si-B amorphous alloys.

1987

$^{61}\mathrm{Ni}$ M\"ossbauer measurements at 4.2 K have been performed on (${\mathrm{Fe}}_{\mathrm{x}}$${\mathrm{Ni}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${)}_{77}$${\mathrm{Si}}_{1013}$ amorphous alloys with x=0.0, 0.1, and 0.9. Ni atoms in ${\mathrm{Ni}}_{77}$${\mathrm{Si}}_{10}$${\mathrm{B}}_{13}$ bear no magnetic moment, whereas in (${\mathrm{Fe}}_{0.1}$${\mathrm{Ni}}_{0.9}$${)}_{77}$${\mathrm{Si}}_{10}$${\mathrm{B}}_{13}$ and (${\mathrm{Fe}}_{0.9}$${\mathrm{Ni}}_{0.1}$${)}_{77}$${\mathrm{Si}}_{10}$${\mathrm{B}}_{13}$ their moments are, respectively 0.38${\ensuremath{\mu}}_{B}$ and 0.65${\ensuremath{\mu}}_{B}$. Our results, together with the literature data, show that Ni atoms in Fe-…

Fifty Years of Mössbauer Spectroscopy in Solid State Research - Remarkable Achievements, Future Perspectives

2011

Mossbauer spectroscopy was founded more than fifty years ago based on an outstanding discovery by the young German physicist Rudolf Ludwig Mossbauer while working on his Ph.D. thesis. He discovered the recoilless nuclear resonance fluorescence of gamma radiation and was awarded the Nobel Prize in Physics in 1961 as one of the youngest recipients of this most prestigious award. His discovery led to the development of a new technique for measurements of hyperfine interactions between nuclear moments and electromagnetic fields. This method, with highest sharpness of tuning of 10–13, yields information on valence state, symmetry, magnetic behavior, phase transition, lattice dynamics and other s…

61Ni MÖSSBAUER EFFECT STUDIES OF THE FERRIMAGNETIC SPINEL NiCr2O4 IN AN APPLIED MAGNETIC FIELD

1980

An unambiguous procedure for discovering relaxation influence on M�ssbauer spectra

1994

A mathematical procedure which gives an opportunity to distinguish between relaxation and distribution mechanisms of the Mossbauer line broadening is proposed. It is based on the method of Mossbauer line sharpening developed recently [1] and allows one to answer unambiguously the question whether or not relaxation manifests itself in Mossbauer measurements by examining the wings of the spectrum. The procedure is applied to the spectra of high spin ferric metmyoglobin and (Fe0.65Ni0.35)1−xMnx alloys. Analysis of the metmyoglobin spectra manifests the presence of the relaxation influence in the temperature range 10 K≦T≦100 K. Analysis of the alloy spectra shows that for the temperatures 4 K≦T…