Current-induced magnetization switching and CPP-GMR in 30 nm Φ scale spin valves fabricated using EB-assisted CVD hard masks

In this study, current-perpendicular-to-plane great magnetoresistance (CPP-GMR) spin valves with the minimum pillar width of 34 nm Φ were successfully fabricated using EB-assisted chemical-vapor-deposition (CVD) hard masks. An area of the obtained magnetic cell is about one order smaller compared with those fabricated with normal EB or photo lithography technique. Measurement of transport properties such as current-induced magnetization switching (CIMS) and MR were demonstrated in such spin valves with various pillar widths. Dependence of the CPP-MR properties on the milled pillar width was discussed. In the case of 66 nm Φ width in particular, the MR by external magnetic field switching and CIMS were 0.4% and 0.3%, respectively. The critical switching current Ic was ∼40 mA (Jc ∼ 9 x 108 A/cm2). In the case of smaller width, only MR by external magnetic field was observed.