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371.
A micromagnetic approach was used to simulate ferromagnetic resonance frequency (FMR) profiles of perpendicular granular CoCrPt-oxide thin films. From the obtained FMR line-width we computed the effective damping constant. The influence of the intergranular exchange on the effective damping was investigated, showing an increase in the damping constant with increase in intergranular exchange coupling. Moreover, the effective damping constant increases with decrease in mesh size of the model, and eventually saturates for mesh sizes of about 1 nm. These dependencies are explained in terms of different modes that can be excited in the granular medium due to interactions between the individual spins. 相似文献
372.
L.J. LiW.J. Lu X.D. ZhuX.B. Zhu Z.R. YangW.H. Song Y.P. Sun 《Journal of magnetism and magnetic materials》2011,323(21):2536-2541
The low-Mn-intercalated compounds 2H-MnxTaS2 (x≤0.1) single crystals were successfully grown via the iodine chemical vapor transport technique; the electrical and magnetic properties have been investigated systematically. No signs of charge density wave and superconductivity transitions appear down to 2 K even when x=0.02, while a small resistivity upturn has been observed in the low-temperature region for MnxTaS2 samples. A substantial magnetocrystalline anisotropy is observed and the Mn magnetic moments lie mainly parallel to the ab-plane. The glass behavior was observed in the low-temperature region firstly from the ac susceptibility measurement, the freezing of the glass may contribute to the upturn of the resistivity. 相似文献
373.
374.
《Current Applied Physics》2014,14(5):685-687
The effect of the replacement of Fe by Co or B on the thermal stability and soft magnetic properties of the Fe-based amorphous metallic ribbons with Fe(87−x−y)CoxTi7Zr6By (x = 10, 20% and y = 8, 10, 12%) produced by melt-spinning technique was investigated. For the melt-spun amorphous ribbons, the values of saturation magnetization and coercivity were observed to range from 107.00 to 152.38 emu/g and from 0.012 to 0.446 Oe, respectively. The thermal properties such as Tg, Tx, and ΔTx were in the range of 796.7–809.6 K, 840.2–853.5 K, and 35.8–54.5 K, respectively. In the Fe–Co–Ti–Zr–B alloys, the Co substitution for Fe improved the soft magnetic properties but decreased the thermal stability. For magnetic properties, the coercivity (Hc) decreased and saturation magnetization (Ms) increased by the addition of Co. However, the supercooled liquid region (ΔTx) decreased by the addition of Co. Meanwhile, the B substitution for Fe had no meaningful change on the thermal stability and soft magnetic properties. The amorphous ribbon of Fe59Co20Ti7Zr6B8 exhibited the best soft magnetic properties such as the low coercivity of 0.025 Oe and the high saturation magnetization of 152.38 emu/g. 相似文献
375.
Kei FujiwaraTakayuki Ishida 《Polyhedron》2011,30(18):3073-3078
Five oxovanadium(IV) complexes [VO(X4salen)] have been prepared and characterized, where each benzene ring was substituted with two halogen atoms in salen (H2salen = N,N′-disalicylideneethylenediamine). The X-ray diffraction study on 3,3′,5,5′-tetrachloro-, 3,3′,5,5′-tetrabromo-, and 4,4′,6,6′-tetrachlorosalen derivatives clarified their polymeric structure with the (-VO-)n repeating unit. The interatomic V···V distances are 3.710(3), 3.695(3), and 3.749(3) Å, respectively, being shorter than that of known [VO(salpn)] (3.83 Å; H2salpn = N,N′-disalicylidenepropylenediamine). The exchange coupling parameters (J) were determined by fitting the magnetic susceptibility data to the one-dimensional ferromagnetic model, giving 2J/kB = 8.2-16 K, which are the largest in the [VO(salen)] and [VO(salpn)] family. 相似文献
376.
Zulhadjri B. Prijamboedi N. Mufti T.T.M. Palstra 《Journal of solid state chemistry》2011,184(5):1318-1323
Doping of manganese (Mn3+/Mn4+) into the Aurivillius phase Pb1−xBi4+xTi4−xMnxO15 was carried out using the molten salt technique for various Mn concentrations (x=0, 0.2, 0.4, 0.6, 0.8, and 1). Single phase samples could be obtained in the composition range with x up to 0.6 as confirmed by X-ray and neutron diffraction analysis. Dielectric measurements show a peak at 801, 803, 813 and 850 K for samples with x=0, 0.2, 0.4, and 0.6, respectively, related to the ferroelectric transition temperature (Tc). The main contribution of the in-plane polarization for x≤0.2 which was calculated from the atomic positions obtained by the structure analysis is the dipole moment in the Ti(1)O6 layer; however, for x≥0.4 the polarization originates from the dipole moment in the Ti(2)O6 layer. Mn doping in the Pb1−xBi4+xTi4−xMnxO15 does not show any long range magnetic ordering. 相似文献
377.
王东 《原子与分子物理学报》2018,35(6)
采用能量极小原理研究了Permalloy(Py)/Cu/Co/NiO多层膜结构中层间耦合强度和应力各向异性场对薄膜共振频率的影响,得到共振频率随外磁场强度变化关系式.结果发现外应力场强度和方向对系统共振频率的影响在本文中要强于层间耦合强度和交换各向异性场.外应力场方向对光学模共振频率的影响强于声学模,而外应力场强度对声学模共振频率的影响强于光学模. 相似文献
378.
《Physics letters. A》2019,383(22):2662-2667
We present a theoretical study on the spin-dependent transport through the ferromagnetic graphene nanoribbons in the presence of a magnetic and an in-plane ac electric field, and find that when the ac field is applied, in the two-terminal ferromagnetic graphene device, for the parallel configurations of the electrodes' magnetizations, the width of the even-number conductance plateaus decrease, the new conductance plateaus appear at the odd-number positions, and the even-number conductance plateaus at the high energy are quenched under the sufficiently strong ac field. In contrast, for the antiparallel configuration of the electrodes' magnetizations, the odd-plateaus of the conductance shrink, and the new plateaus developed at the even-number positions. The magnetic resistance exhibits a successive rectangular-like oscillation structure close to the band edge, whereas experiences an alternative transition between the sharp peak and dip near the zero energy with increasing the ac field strength. In the six-terminal ferromagnetic graphene device, the variations of the longitudinal and Hall resistances' plateaus as well as the addition of the new quantized plateaus with the rise of the ac field strength are also revealed. 相似文献
379.
Nguyen Hoa Hong Chul-Kwon Park A.T. Raghavender Antoine Ruyter Ekaterina Chikoidze Yves Dumont 《Journal of magnetism and magnetic materials》2012
Theory has predicted that high temperature ferromagnetism (FM) should be found in cubic fake-diamonds, Mn-doped ZrO2. Experimentally, it is shown that Mn-doped ZrO2 ceramics are not ferromagnetic, but the nanosized Mn-doped ZrO2 thin films grown on LaAlO3 substrates can be ferromagnets with TC above 400 K. The largest saturated magnetic moment (Ms) is huge as of about 230 emu/cm3 for the Mn0.05Zr0.95O2 films, and it decreases as the Mn content increases. The intrinsic FM is strongly associated with the cubic structure of Mn-doped ZrO2, and the Mn–Mn interactions via oxygen intermediates are important. No electrical conductivity is observed. Mn-doped ZrO2 thin films can be truly considered as excellent candidates for spintronic applications. 相似文献
380.
Jie ChenZhida Han Bin Qian Ping ZhangDunhui Wang Youwei Du 《Journal of magnetism and magnetic materials》2011,323(2):248-251
The effects of Al substitution on the phase transitions and magnetocaloric effect of Ni43Mn46Sn11−xAlx (x=0-2) ferromagnetic shape memory alloys were investigated by X-ray diffraction and magnetization measurements. With the increase of Al content, the cell volume decreases due to the smaller radius of Al, and the martensitic transformation temperature increases rapidly, while the Curie temperature of austenitic phase shows a small increase. A large positive and a negative magnetic entropy change were observed near the first-order martensitic transition and the second-order magnetic transition, respectively. The magnetic entropy changes, hysteresis behavior, and refrigerant capacity near the two transitions are compared. 相似文献