Fig. 2: Dependence of proximity-induced AHE and current-induced magnetization switching on the CGT layer thickness.
a μ0Hz dependence of the Hall resistance Ryx in the CGT/BST (x = 0.5, 6 nm) bilayer devices with various CGT thickness (tCGT = 2.9, 4.6, 5.8, and 12 nm) at 2 K. RyxAH is the remnant value of Ryx at μ0Hz = 0 T. b Magnetization switching with current pulses Jx, as tracked by the variation of Hall resistance Ryx (left axis) of the CGT (tCGT = 2.9 nm)/BST (x = 0.5, 6 nm) device under in-plane magnetic fields μ0Hx = +0.1 T (blue) and −0.1 T (red) at 2 K. Right axis is the switching ratio defined as Ryx/RyxAH. The broken lines represent Ryx/RyxAH = 1 for the full switching of magnetization. c Magnetization switching in the CGT/BST devices with various tCGT (=2.9, 4.6, 5.8, 8.1, and 12 nm) under μ0Hx = −0.1 T. d, e The tCGT dependence of the switching current Jxsw (left axis) and the switching ratio of Ryxsw/RyxAH (right axis) (d), and the coefficient ξ [=2eμ0MsHctCGT/(ħjxsw)] representing the efficiency of current-induced magnetization reversal (e). Note that ξ for tCGT = 8 and 12 nm increases up to ~1.4 nm−1, where the Joule heating seemingly improves the efficiency. The inset to e shows the tCGT dependence of the product of the coercive field μ0Hc and the spontaneous magnetization Ms. The horizontal error bars represent the film roughness determined by x-ray reflectivity measurements. The vertical ones for d and e represent the measurement uncertainties. The red broken (d) and solid (e) lines are the guides to the eyes.
