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Training Effect and Hysteretic Behaviour of Angular Dependence of Exchange Bias in Co/IrMn Bilayers 下载免费PDF全文
The training effect and the hysteresis behaviour of the angular dependence of exchange bias are extensively investigated upon the variation of the IrMn layer thickness tXrMn in a series of Co/IrMn bilayers. When tIrMn is very small, both of them are negligible. Then they increase very sharply with increasing tUMn and then reach maxima at almost the same value OftXrMn. Finally they both decrease when tIrMn is further increased. The similar variation trends suggest that these phenomena arise from irreversible change of antiferromagnet spin orientations, according to the thermal activation model. 相似文献
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The realization of perpendicular magnetization and perpendicular exchange bias(PEB)in magnetic multilayers is important for the spintronic applications.NiO(t)/[Ni(4 nm)/Pt(1 nm)]2multilayers with varying the NiO layer thickness t have been epitaxially deposited on SrTiO;(001)substrates.Perpendicular magnetization can be achieved when t<25 nm.Perpendicular magnetization originates from strong perpendicular magnetic anisotropy(PMA),mainly resulting from interfacial strain induced by the lattice mismatch between the Ni and Pt layers.The PMA energy constant decreases monotonically with increasing t,due to the weakening of Ni(001)orientation and a little degradation of the Ni–Pt interface.Furthermore,significant PEB can be observed though NiO layer has spin compensated(001)crystalline plane.The PEB field increases monotonically with increasing t,which is considered to result from the thickness dependent anisotropy of the NiO layer. 相似文献
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用反应溅射方法制备了FeRO(R=Hf, Nd, Dy) 薄膜,并在400℃时对样品进行退火处理,x射线衍射和电子衍射结果显示纳米量级的Fe晶粒镶嵌在非晶氧化物基质中.用面内铁磁共振技术仔细测量了样品的共振吸收谱,并分析了局域磁化强度Ms与晶粒尺寸的关系.制备态样品呈现出显著的面内单轴各向异性,退火后单轴各向异性显著减弱,取而代之的是较弱的磁晶各向异性.利用公式(ω/γ)2=(Hres+HK)(Hres+HK+4πMs)求出局域磁化强度Ms,它随晶粒尺寸减小而减小,在晶粒尺寸为5nm时仅约为Fe体材料饱和磁化强度的30%.局域磁化强度与根据Fe的体积百分比算出的体磁化强度相比偏小,并与晶粒尺寸的倒数呈线性关系,说明在晶粒表面存在较强的磁矩钉扎效应.
关键词:
铁磁共振
局域磁化强度
单轴各向异性
磁晶各向异性 相似文献
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From self-assembly to quantum guiding: A review of magnetic atomic structures on noble metal surfaces 下载免费PDF全文
Recent advances in the study of magnetic atomic structures on noble metal surfaces are reviewed. These include one- dimensional strings, two-dimensional hexagonal superlattices, and novel structures stabilized by quantum guiding. The combined techniques of low-temperature scanning tunneling microscopy, kinetic Monte Carlo simulations, and ab initio calculations reveal that surface-state-mediated adatom-step and adatom-adatom interactions are the driving forces for self- assembly of these structures. The formation conditions are further discussed by comparing various experimental systems and the kinetic Monte Carlo simulations. Using scanning tunneling spectroscopy and tight-binding calculations together, we reveal that the spectra of these well-ordered structures have characteristic peaks induced by electronic scattering processes of the atoms within the local environment. Moreover, it is demonstrated that quantum confinement by means of nano-size corrals has significant influence on adatom diffusion and self-assembly, leading to a quantum-guided self-assembly. 相似文献
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A significant exchange bias(EB) training effect has been observed in sputter deposited FeAu/FeNi bilayers, wherein the exchange field(HE) exhibits a special sign-changeable temperature dependence. Very interestingly, despite the absence of multiple easy axes in the FeAu spin glass(SG) layer, HEdrops abruptly between the first and second magnetic cycles,which is followed by a more gradual continuous change in the subsequent cycles. This training behavior cannot be described by the empirical n-1/2law because of the asymmetric magnetization reversal processes. We propose modifying Binek’s model to include the asymmetric changes of the pinning SG spins at the descending and ascending branches. This new model successfully describes the EB training effect in FeAu/FeNi bilayers. 相似文献
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We investigate the structural,static magnetic and damping properties in two Mn-deficient magnetic Weyl semimetal Co-Mn-Ga(CMG) alloy films,i.e.,Co55Mn18Ga27(CMG1) and Co50Mn18Ga32(CMG2),which were epitaxially grown on MgO(001) substrates.CMG1 has a mixing phase of B2 and L21,larger saturation magnetization(Ms ~760 emu/cm3),stronger in-plane magnetic anisotropy.CMG2 has an almost pure B2 phase,small... 相似文献
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