Over 100% magnetoresistance ratio at room temperature in magnetic tunnel junctions with CuGaSe2 spacer layer

We investigated the structure and magneto-transport properties of magnetic tunnel junctions (MTJs) consisting of half-metallic Co2FeGa0.5Ge0.5 ferromagnetic electrodes and a semiconductive CuGaSe2 interlayer. The magnetoresistance (MR) ratio reaches more than 100% at room temperature and nearly 250% at 30 K with the resistance area product (RA) smaller than 1 Ω μm2. Microstructural analysis clarified that Co and Fe atoms diffuse into the CuGaSe2 layer, which can be a possible reason for the scattering of RA values but poorly affect the MR ratio itself. Our findings stress the potential of semiconductor barriers in MTJs for spintronics application that requires low RA.We investigated the structure and magneto-transport properties of magnetic tunnel junctions (MTJs) consisting of half-metallic Co2FeGa0.5Ge0.5 ferromagnetic electrodes and a semiconductive CuGaSe2 interlayer. The magnetoresistance (MR) ratio reaches more than 100% at room temperature and nearly 250% at 30 K with the resistance area product (RA) smaller than 1 Ω μm2. Microstructural analysis clarified that Co and Fe atoms diffuse into the CuGaSe2 layer, which can be a possible reason for the scattering of RA values but poorly affect the MR ratio itself. Our findings stress the potential of semiconductor barriers in MTJs for spintronics application that requires low RA.

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