Cao Shi, Street M, Wang Junlei, Wang Jian, Zhang Xiaozhe, Binek Ch, Dowben P A
Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, United States of America.
J Phys Condens Matter. 2017 Mar 15;29(10):10LT01. doi: 10.1088/1361-648X/aa58ba. Epub 2017 Jan 11.
From the Cr 2p x-ray magnetic circular dichroism signal, there is clear evidence of interface polarization with overlayers of both Pd and Pt on chromia (CrO). The residual boundary polarization of chomia is stronger for a Pt overlayer than in the case of a Pd overlayer. The reduction of chromia boundary magnetization with a paramagnetic metal overlayer, compared to the free surface, is interpreted as a response to the induced spin polarization in Pt and Pd. Magnetization induced in a Pt overlayer, via proximity to the chromia boundary magnetization, is evident in the polar magneto-optical Kerr measurements. These results are essential to explainations why Pt and Pd are excellent spacer layers for voltage controlled exchange bias, in the [Pd/Co] /Pd/CrO and [Pt/Co] /Pt/CrO perpendicular magneto-electric exchange bias systems. The findings pave the way to realize ultra-fast reversal of induced magnetization in a free moment paramagnetic layer, with possible application in voltage-controlled magnetic random access memory.
从Cr 2p X射线磁圆二色性信号可以清楚地证明，在氧化铬（CrO）上覆盖Pd和Pt时存在界面极化。对于Pt覆盖层，氧化铬的残余边界极化比Pd覆盖层的情况更强。与自由表面相比，顺磁金属覆盖层使氧化铬边界磁化强度降低，这被解释为对Pt和Pd中诱导自旋极化的响应。在极磁光克尔测量中，通过靠近氧化铬边界磁化强度在Pt覆盖层中感应出的磁化强度是明显的。这些结果对于解释为什么在[Pd/Co] /Pd/CrO和[Pt/Co] /Pt/CrO垂直磁电交换偏置系统中Pt和Pd是用于电压控制交换偏置的优秀间隔层至关重要。这些发现为在自由矩顺磁层中实现感应磁化的超快反转铺平了道路，可能应用于电压控制磁随机存取存储器。
