Development of Spin Valve type of Static Memory Devices using GMR Effect

利用双离子束溅射装置在Fe缓冲层上沉积了厚度分别为10~35A的Ni-Fe和Cu层组成的巨磁多层膜。将辅助离子辐射到Ni-Fe和CuLayR界面，研究了巨磁电阻(GMR)效应对亚离子辅助电压V_<SUB>从0到350V的变化。虽然磁阻比的幅度略有降低，但磁阻的场敏感度在离子辅助辐射作用下得到了较大的改善，在V<160V处达到最大值。针对多层膜上常见的用于施加交换偏置磁场的Fe-Mn层耐蚀性差、易被氧化的问题，我们提出了一种倒置型自旋阀结构，即直接在衬底上沉积FeMn层，在其上沉积Ni-Fe/Cu/Ni-Fe层。通过在(111)取向良好的Ni-Fe薄膜上沉积和离子辅助辐射，我们成功地沉积了(111)取向的FeMn薄膜。在(111)取向的FeMn薄膜上沉积的Ni-Fe/Cu/Ni-Fe薄膜具有较好的磁阻比和良好的场敏性能。这种多层膜的交换偏置电场约为20Oe，可作为自旋阀器件使用，似乎有可能作为静态存储器件应用于光刻技术。

The giant magnetic multilayrs composed of Ni-Fe and Cu layrs whose thickness were from 10 to 35 A each were deposited on Fe buffer layr by using the dual ion beam sputtering apparatus. Assist ions were radiated to the interfaces between Ni-Fe and Cu layr and the change of giant magneto-resistance (GMR) effect on sub ion assist voltage V_<sub> from 0 to 350 V was investigated. Although the amplitude of magneto-resistivity (MR) ratio was slightly decreased, the field sensitivity of magneto-resistance was fairly improved by ion assist radiation and took the maximum value at V_<sub> of 160 V.Since Fe-Mn layr, which is commonly deposited on top of the multilayrs and used for applying exchange bias field, has poor corrosion resistivity and is easily to be oxidezed, we proposed the reversed type spin valve structure, in which FeMn layr is deposited on substrate directly and Ni-Fe/Cu/Ni-Fe layrs was deposited on it. We succeeded to deposit FeMn layr with (111) orientation by deposited on Ni-Fe layr with well (111) orientation and ion-assist radiation. Ni-Fe/Cu/Ni-Fe layrs deposited on FeMn layr with (111) orientation possessed relatively well MR ratio and excellent field sensitivity. The exchange bias field of about 20 Oe was achieved in this type of multilayrs and it worked as spin valve device.It seemed that the spin valve multilayrs deposited in this study has possibility to be applied as static memory device by using lithographic technology.