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Effects of light irradiation and thermal heating on interlayer coupling in Fe-Si ferromagnetic metal/semiconductor superlattices

光照射和热加热对 Fe-Si 铁磁金属/半导体超晶格层间耦合的影响

基本信息

批准号：
20310078
负责人：
YOSHITAKE Tsuyoshi
金额：
$ 12.73万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

项目摘要

Spin-dependent phenomena have recently received much attention. Particularly, interlayer couplings between ferromagnetic layers separated by nonmagnetic metal and insulator spacer layers have been investigated to a large extent since they can induce the spin-dependent scattering of conduction carriers and spin-dependent tunneling, which are exploited for achieving the giant magnetoresistance (GMR) and tunnel magnetoresistance (TMR) effects, respectively. At present, the switching of interlayer couplings is made by applied magnetic fields. In this study, in order to switch them by the other methods such as light irradiation, thermal heating, and current injection, semiconducting interlayers were employed. Actually ferromagnetic Fe_3Si/semiconducting FeSi_2 superlattices were prepared by sputtering and interlayer couplings were attempted to be switched by their methods. Although current in plane (CIP) films exhibited a change in the electrical resistivity for irradiation with a 1.3-μm la … More ser, which was expected to be due to a change in the interlayer coupling from antiferromagnetic (AF) to ferromagnetic (F) coupling, the change in the electrical resistivity was extremely small to be detected. Thus, we adapted current perpendicular plane (CPP) geometry for the detection. Owing to that, the magnetoresistance ratio was enhanced to be approximately 10%. This value is an order of magnitude larger than that of the CIP films. The CPP films exhibited hysteresis loops for the injection current. From the change in the hysteresis loop under magnetic field, the origin of the hysteresis loops was expected to be a change in the interlayer coupling. It was confirmed that the interlayer coupling of the CPP films was obviously changed from AF coupling at room temperature to F coupling at temperatures of lower than 100 K. The CPP films also exhibited temperature-dependent interlayer couplings : AF coupling in a direction perpendicular to the plane induced at room temperature gradually weakened with a decrease in temperature and it finally disappeared at low temperatures. Less

自旋相关现象最近受到了广泛的关注。特别地，由金属间层和绝缘体间隔层分隔的铁磁层之间的层间耦合已经在很大程度上被研究，因为它们可以诱导传导载流子的自旋相关散射和自旋相关隧穿，这分别用于实现巨磁电阻（GMR）和隧道磁电阻（TMR）效应。目前，层间耦合的开关是通过外加磁场实现的。在这项研究中，为了切换它们的其他方法，如光照射，热加热，和电流注入，半导体夹层。用溅射法制备了铁磁Fe_3Si/半导体FeSi_2超晶格，并尝试了用这种方法实现层间耦合的转换。虽然面内电流（CIP）薄膜在1.3 μm激光辐照下电阻率发生了变化， ...更多信息 ser，这被预期是由于层间耦合从反铁磁（AF）耦合到铁磁（F）耦合的变化，电阻率的变化非常小，无法检测到。因此，我们调整了电流垂直平面（CPP）的几何检测。由此，磁阻比提高到约10%。该值比CIP膜的值大一个数量级。CPP膜的注入电流表现出滞后回线。从磁场下磁滞回线的变化来看，磁滞回线的起源预计是层间耦合的变化。实验结果表明，CPP薄膜的层间耦合由室温下的AF耦合转变为低于100 K时的F耦合。CPP薄膜还表现出温度依赖性的层间耦合：在室温下诱导的垂直于平面方向的AF耦合随着温度的降低而逐渐减弱，并最终在低温下消失。少