Pt/GdFeCo/Pt多层膜的磁性和反常霍尔效应研究

亚铁磁材料因具有反铁磁排列的子晶格磁矩而表现出诸多丰富的物理性质,在磁信息存储和逻辑领域具有广阔的应用前景.本文采用磁控溅射方法在热氧化的硅基片上制备了Pt/GdFeCo(t)/Pt多层膜,系统研究了亚铁磁GdFeCo厚度对多层膜的表面形貌、结构、磁性以及反常霍尔效应(AHE)的影响.结构测试表明薄膜表面粗糙度较小,且GdFeCo层为非晶态;实验中利用GdFeCo层厚度可有效控制Gd元素含量,从而调控GdFeCo趋近反铁磁态特性的磁矩补偿点;通过重金属强自旋轨道耦合效应(SOC)和非晶态亚铁磁薄膜面内压应力,实现了良好垂直各向异性(PMA);进一步阐明了亚铁磁薄膜中磁性和反常霍尔效应的内在产生机制以及磁矩补偿点与温度的内在关系.这些结果为构建新一代低功耗自旋电子器件奠定基础.

Investigation on Magnetism and Anomalous Hall Effect of Pt/GdFeCo/Pt Multilayer Films

Due to antiferromagnetic arrangement of sublattice magnetic moments, ferrimagnetic materials exhibit many rich physical properties, and possess wide application prospects in the fields of magnetic information storage and logic. In this paper, Pt/GdFeCo(t)/Pt multilayer films were prepared on thermally oxidized Si substrate by magnetron sputtering. The influences of the thickness of ferrimagnetic GdFeCo on the surface morphology, structure, magnetic properties, and anomalous Hall effect (AHE) of multilayer films were systematically studied. The structure analysis of the samples shows that the surface roughness is very small, and the GdFeCo layer is amorphous. The content of the Gd element can be effectively tuned by changing the thickness of GdFeCo layer, and then the magnetic moment compensation point of the GdFeCo representing the antiferromagnetic state can be adjusted. An excellent perpendicular magnetic anisotropy (PMA) is realized by the strong spin-orbit coupling (SOC) effect of heavy metals and the in-plane compressive stress of the amorphous ferrimagnetic films. The intrinsic mechanism of magnetism and anomalous Hall effect in ferrimagnetic films and the intrinsic relationship between magnetic moment compensation point and temperature are clarified. These results lay the foundation for the construction of a new generation of low-power spintronic devices.