Room temperature magnetoresistance in Sr₂FeMoO₆/SrTiO₃/Sr₂FeMoO₆trilayer devices

We report the room temperature magnetoresistance in Sr 2 FeMoO 6 based magnetic tunnel junctions (MTJs). The micrometre-sized (SFMO/STO/SFMO) devices were grown by pulse laser deposition. The crystal structure and phase purity of SFMO layers were examined by X-ray diffraction, which shows the single phase formation of ordered polycrystalline SFMO thin film without any impurity phases. The FESEM micrograph clearly shows the presence of an ultrathin STO barrier layer. The magnetization measurements show the good ferromagnetic loop behaviour and Curie temperature ( T C ) well above 375 K, which indicate fairly high-quality growth of SFMO thin films. The current–voltage curve of the MTJ devices at room temperature exhibited nonlinear and asymmetric behaviour in agreement with the predictions of tunnel conductance. The observed large tunnelling magnetoresistance (TMR ∼ 7%) at room temperature was attributed to spin-dependent tunnelling across a uniform ultrathin STO tunnel barrier sandwiched between two identical SFMO (bottom and top) electrodes in MTJ devices.