Spin-dependent CPP transport in SnOx/Co multilayers

In this article, we report on a spin-dependent CPP transport observed in novel semiconductive-oxide/ferromagnet multilayers of [SnOx(t nm)/Co(30 nm)/SnOx(t nm)/Co(2 nm)/NiFe(16 nm)/Co(2 nm)]×9, deposited with a multi-target magnetron sputtering system. The measured electrical conductivity σ shows a linear behaviour in the ln(σ) vs. T-1 plot at the temperature range of 120x layer. The thermal activation energy for the transport was evaluated as an order of 0.01 erg from the linear part of the plot. Though the values of α show marked scattering, the mean value decreases from +3.0×10-3 (t = 4 nm) to -3.5×10-3 (t = 32 nm) with the increase of t. Negative magnetoresistance was observed in two orthogonal directions of in-plane external fields. An MR ratio of 0.24% (ΔR = 0.20 Ω, Rs = 83 Ω) is observed at room temperature for the multilayer with t = 16 nm, where the saturation field is 350 Oe.