SrRuO_(3)薄膜中自旋轨道力矩效率和磁矩翻转的晶向调控

Crystal orientation regulation of spin-orbit torque efficiency and magnetization switching in SrRuO3 thin films

过渡金属氧化物SrRuO_(3)薄膜因具有较大且可调的电荷流-自旋流互转换效率而成为自旋轨道力矩(SOT)器件中备受关注的自旋源材料.然而,目前对SOT效率的调控主要集中在衬底外延应力调节.本文研究了晶体取向对SrRuO_(3)薄膜SOT性能的调控作用.制备了(111)取向SrRuO_(3)/CoPt异质结构,发现其SOT效率高达0.39,自旋霍尔电导达2.19×10^(5)■/(2e)Ω^(–1)·m^(–1),分别较(001)取向提高了86%和369%.此外,在SrRuO_(3)(111)器件中实现了低至2.4×10^(10)A/m^(2)临界电流密度下的电流驱动的垂直磁化翻转,较(001)晶向降低了37%.这些结果表明,晶体取向是显著提升SrRuO_(3)基SOT器件综合性能的有效途径,为发展高效自旋电子器件提供了新思路.

Spintronic devices utilize the spin property of electrons for the storage,transmission,and processing of information,and they possess inherent advantages such as low power consumption and non-volatility,thus attracting widespread attention from both academia and industry.Spin-orbit torque(SOT)is an efficient method of manipulating magnetic moments through using electric current for writing,controlling the spin-orbit coupling(SOC)effect within materials to achieve the mutual conversion between charge current and spin current.Enhancing the efficiency of charge-spin conversion is a critical issue in the field of spintronics.Strontium ruthenate(SRO)in transition metal oxides(TMO)has attracted significant attention as a spin source material in SOT devices due to its large and tunable charge-to-spin conversion efficiency.However,current research on SOT control in SRO primarily focuses on utilizing substrate strain,with limited exploration of other control methods.Crystal orientation can produce various novel physical properties by affecting material symmetry and electronic structure,which is one of the important means to control the properties of TMO materials.Considering the close correlation between the SOT effect and electronic structure as well as surface states,crystal orientation is expected to affect SOT properties by adjusting the electronic band structure of TMO.This work investigates the effect of crystal orientation on the SOT performance of SrRuO3 film and develops a novel approach for SOT control.The(111)-oriented SRO/CoPt heterostructures and SOT devices are prepared by using pulse laser deposition,magnetron sputtering,and micro-nano processing techniques.Through harmonic Hall voltage(HHV)measurements,we find that the SOT efficiency reaches 0.39,and the spin Hall conductivity attains 2.19×105/2eΩ-1·m-1,which are 86%and 369%higher than those of the(001)orientation,respectively.Furthermore,current-driven perpendicular magnetization switching is achieved in SrRuO3(111)device at a low critical current density of 2.4×1010 A/m2,which is 37%lower than that of the(001)orientation.These results demonstrate that the crystal orientation can serve as an effective approach to significantly enhancing the comprehensive performance of SrRuO3-based SOT devices,thus providing a new idea for developing high-efficiency spintronic devices.