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Influences of Bi2O3/V2O5 Additives on the Microstructure and Magnetic Properties of Lithium Ferrite 下载免费PDF全文
Lithium ferrite materials with different concentrations of Bi2O3 and V2O5 additives are prepared by the conventional ceramic technique. The x-ray diffraction analysis proves that the additives do not affect the final crystal phase of the lithium ferrite in our testing range. Both Bi2O3 and V2O5 additives could promote densification and lower sintering temperature of the lithium ferrite. The average grain size first increases, and then gradually decreases with the Bi2O3 content. The maximal grain size appears with 0.25 wt% Bi2O3. The average grain size first increases, and then is kept almost unchanged with the V2O5 content. The maximal average grain size of the samples with V2O5 additive is much smaller than that of the samples with Bi2O3 additive. Furthermore, the V2O5 additive more easily enters the crystal lattice of the lithium ferrite than the Bi2O3 additive. These characteristics evidently affect the magnetic properties, such as saturation flux density, ratio of remanence Br to saturation flux density Bs, and coercive force of the lithium ferrite. The mechanisms involved are discussed. 相似文献
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利用液相外延工艺在钆镓石榴石衬底上制得了单晶(BiTm)_3(GaFe)_5O_(12)膜,研究了晶格失配应力对其磁畴结构的影响.研究发现,生长速率越快,膜的晶格常数越大;晶格失配应力可以在一定范围内调整膜的垂直各向异性;随着晶格失配应力由较大张应力逐渐转变为较大压应力,磁畴形状先由磁泡畴转变成迷宫畴,然后转变为过渡态部分弯曲的条状畴,最终转变为整齐排列的条状畴;失配应力同时对畴宽也有影响,膜受到的失配应力越大,畴宽越大.这一实验研究对基于控制晶格失配应力来调控单晶膜的各向异性和磁畴结构有指导意义. 相似文献
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Flexible tuning microwave permeability spectrum in [ferromagnet/antiferromagnet]_n exchange-biased multilayer stack structure 下载免费PDF全文
NiFe/[IrMn/NiFe/IrMn] 5 /[NiFe/IrMn] 4 /NiFe structured exchange-biased multilayer films are designed and prepared by magnetron sputtering. The static and the microwave magnetic properties are systematically investigated. The results reveal that adding a partially pinned ferromagnetic layer can effectively broaden the ferromagnetic resonance linewidth toward the low frequency domain. Moreover, a wideband multi-peak permeability spectrum with a 3.1-GHz linewidth is obtained by overlapping the spectra of different partially pinned ferromagnetic layers and [antiferromagnet/ferromagnet/antiferromagnet] n stacks. Our results show that the linewidth of the sample can be feasibly tuned through controlling the proper exchange bias fields of different stacks. The designed multilayered thin films have potential application for a tunable wideband high frequency noise filter. 相似文献
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Theoretical Investigations on the Off-Center Displacement of Co2+ in SrO by Analyzing Its Anisotropic g Factors 下载免费PDF全文
The off-center displacement of Co^2+ ion in SrO crystal is investigated by analyzing its anisotropic g factors gx, gy and gz through diagonalization of the 6 × 6 energy matrix within ^4T1 ground state for a 3d^7 ion under rhombic symmetry. In the matrix, the contributions from the admixtures of various J(= 1/2, 3/2, 5/2) states and the fourth-order term Dn of rhombic crystal-fields and the ligand orbitals and spin-orbit coupling interactions, which are usually ignored in the previous studies, are considered. Both g factors (gx = 4.172, gy = 5.004 and gz = 2.133) and the off-displacement value (△ R ≈ 0.023 am) show good agreement with the experimental data. 相似文献
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Effects of Layer Deposition Sequence on Microstructure and Magnetostatic Coupling of Spin-Valves with Amorphous CoNbZr Layer 总被引:1,自引:0,他引:1 下载免费PDF全文
We investigate spin-valve sandwiches with thin amorphous CoNbZr as soft layers. The magnetoresistance (MR), microstructure, and magnetostatic coupling are studied in these sandwiches with different layer deposition sequences. For the CoNbZr/Cu/Co sandwich, the CoNbZr underlayer provides a smoother surface on which smooth Cu and Co layers can subsequently grow. The Cu spacer is dense and pinholes-free, leading to a good ““spin valve““ effect with a larger MR ratio of 3.8%. For the Co/Cu/CoNbZr sandwich, however, the Cu spacer is rough and pinholes were observed, which could induce a direct ferromagnetic coupling. Correlated rougher surfaces on both the sides of the Cu spacer were also observed, giving rise to an ““orangepeel““ coupling of about O. 105 erg/cm^-2. This strong ferromagnetic coupling in Co/Cu/CoNbZr results in a lower MR ratio of 1.6%. Moreover, upon proper thermal annealing, the CoNbZr/Cu/Co has a larger MR enhancement and a superior thermal stability to 350℃ due to the dense and homogenous structure in the spacer layer. 相似文献
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A novel design model based on the slant multi-phase filtering model is presented. A magnetic linear encoder with sinusoidal output voltage waveform has been investigated, and the improved sinusoidal output waveform can be reasily acquired. A minimum 6% of distortion factor, when the difference of slant phase is 2π/3, is observed. It is found that the Wheatstone bridge type sensor, made of NiFe(450A)/NiO(300A) bilayers deposited on Si (001) substrate, can enhance both output signal and thermal stability, and then can be widely used in the field of magneto-resistive sensor. 相似文献
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