Search results for "Magnetization"
showing 10 items of 550 documents
Slow relaxation of the magnetization in a {CoIIIMnIII} heterometallic brick-wall network
2021
Abstract The use of the cyanide-bearing dicobalt(III) complex (PPh4)2[Co2III(μ−2,5-dpp)(CN)8] as a metalloligand towards [Mn(salen)(H2O)]ClO4 afforded the heterobimetallic two-dimensional compound of formula [{MnIII(salen)}2{(μ-NC)4Co2III(μ−2,5-dpp)(CN)4}]n (1) [PPh4+ = teraphenylphosphonium cation, 2,5-dpp = 2,5-bis(2-pyridyl)pyrazine and H2salen = N,N’-ethylenebis(salicylideneimine)] whose structure has been determined by single crystal X-ray diffraction. Compound 1 exhibits a neutral brick-wall structure, where each [Co2III(μ−2,5-dpp)(CN)8]2− unit adopts a tetrakis-monodentate bridging mode towards four {MnIII(salen)}+ fragments through four of its eight cyanide ligands. Each cobalt(III)…
Efficient conversion of orbital Hall current to spin current for spin-orbit torque switching
2021
Spin Hall effect, an electric generation of spin current, allows for efficient control of magnetization. Recent theory revealed that orbital Hall effect creates orbital current, which can be much larger than spin Hall-induced spin current. However, orbital current cannot directly exert a torque on a ferromagnet, requiring a conversion process from orbital current to spin current. Here, we report two effective methods of the conversion through spin-orbit coupling engineering, which allows us to unambiguously demonstrate orbital-current-induced spin torque, or orbital Hall torque. We find that orbital Hall torque is greatly enhanced by introducing either a rare-earth ferromagnet Gd or a Pt in…
Magnetic-field-induced anisotropic curvature elasticity of a vesicle membrane containing magnetic polyions
2000
Interaction between a charged membrane and the electrolyte solution containing magnetic polyions is considered. A self-magnetic field, which arises due to the nonhomogeneous magnetic particle distribution near a charged membrane increases the effective charge screening length for the parts of a membrane normal to a magnetic field. The anisotropy of elastic properties of a membrane depending on the screening length is calculated on the basis of the curvature expansion. It is shown that due to diminishing of the spontaneous curvature for the parts of a membrane normal to a magnetic field there are two competing mechanisms of the ferrovesicle shape transformation under the influence of a magne…
Quasi-one-dimensional quantum spin liquid in the $\rm {Cu(C_4H_4N_2)(NO_3)_2}$ insulator
2015
We analyze measurements of the magnetization, differential susceptibility and specific heat of quasi-one dimensional insulator Cu(C$_4$H$_4$N$_2$)(NO$_3$)$_2$ (CuPzN) subjected to magnetic fields. We show that the thermodynamic properties are defined by quantum spin liquid formed with spinons, with the magnetic field tuning the insulator CuPzN towards quantum critical point related to fermion condensation quantum phase transition (FCQPT) at which the spinon effective mass diverges kinematically. We show that the FCQPT concept permits to reveal and explain the scaling behavior of thermodynamic characteristics. For the first time, we construct the schematic $T-H$ (temperature---magnetic field…
Energy scales and magnetoresistance at a quantum critical point
2009
The magnetoresistance (MR) of CeCoIn_5 is notably different from that in many conventional metals. We show that a pronounced crossover from negative to positive MR at elevated temperatures and fixed magnetic fields is determined by the scaling behavior of quasiparticle effective mass. At a quantum critical point (QCP) this dependence generates kinks (crossover points from fast to slow growth) in thermodynamic characteristics (like specific heat, magnetization etc) at some temperatures when a strongly correlated electron system transits from the magnetic field induced Landau Fermi liquid (LFL) regime to the non-Fermi liquid (NFL) one taking place at rising temperatures. We show that the abov…
Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co(II)6Co(III)3} and {Co(II)Co4(III)} mixed valent complexes and a study o…
2015
We are reporting two new mixed valent Co(ii)/Co(iii) polynuclear complexes, {Co II 6 Co III 3 } and {Co II Co III 4 }, bearing different amount of Co(ii) ions in their cores, through the employment of the multidentate triethanolamine (teaH 3 ) ligand in different stoichiometric ratios. We present a complete picture of the magnetic behaviour of both complexes through a combined usage of the susceptibility, magnetization and X-band EPR data as well as broken-symmetry DFT calculations. Compound 1 shows an atypical spin-only behaviour, probably due to the presence of four and five coordinated Co(ii) sites as well as highly distorted six coordinated Co(ii) ions, promoting a high degree of orbita…
Spin crossover phenomenon of a semi-fluorinated iron (II) complex organized in a Langmuir–Blodgett film
2000
Abstract A new amphiphilic iron (II) complex bearing semi-fluorinated chains has been organized in Langmuir and Langmuir–Blodgett (LB) films. This molecule forms a perfectly stable monolayer at the gas–water interface. Such a film can be transferred easily onto a solid substrate leading to well-defined multilayers. The spin crossover phenomenon occurring in this material has been studied by infrared spectroscopy and magnetization measurements. In the LB film architecture, the iron complex appears to be quenched in a high spin state. This quenching can be released after a thermal annealing and is therefore associated to the specific organization induced by the LB technique.
Current-induced domain wall motion in nanoscale ferromagnetic elements
2011
The manipulation of a magnetic domain wall (DW) by a spin polarized current in ferromagnetic nanowires has attracted tremendous interest during the last years due to fundamental questions in the fields of spin dependent transport phenomena and magnetization dynamics but also due to promising applications, such as DW based magnetic memory concepts and logic devices. We comprehensively review recent developments in the field of geometrically confined domain walls and in particular current induced DW dynamics. We focus on the influence of the magnetic and electronic transport properties of the materials on the spin transfer effect in DWs. After considering the different DW structures in ferrom…
Rod-like ferrites obtained through thermal degradation of a molecular ferrimagnet
2010
This paper presents the characteristics of iron oxides obtained through thermal degradation of a molecular ferrimagnet, {N(n-C4H9)4[Fe II
Slow Magnetic Relaxation in a Co 2 Dy Trimer and a Co 2 Dy 2 Tetramer
2021
The combination of Co(III) and Dy(III) with a compartmental Schiff base ligand (H 3 L = 3-[(2-Hydroxy-3-methoxy-benzylidene)-amino]-propane-1,2-diol), presenting three different coordinating pockets, has allowed the synthesis of two novel Co(III)-Dy(III) complexes: [Co 2 Dy(HL) 4 ]NO 3 ·2CH 3 CN ( 1 ), a rare example of trinuclear linear Co III 2 Dy III complex (and the first with slow relaxation of magnetization in absence of a DC field) and [Co 2 Dy 2 (μ 3 -OH) 2 (HL) 2 (OAc) 6 ]·4.6H 2 O ( 2 ), the first tetranuclear Co III 2 Dy III 2 cluster with a rhomb-like structure where the Co(III) ions are connected along the short diagonal of the rhomb. 1 presents two different relaxation process…