Magnetotransport properties of manganite based magnetic tunnel junctions Available to Purchase

We have studied spin-dependent tunneling in $La2/3Ba1/3MnO3−δ$ based trilayer magnetic tunnel junctions fabricated by pulsed laser deposition. In the heteroepitaxial trilayer structures, a strained $SrTiO3$ layer of different thickness was used as a tunneling barrier. For the junctions with a $SrTiO3$ barrier, the measured tunneling characteristics deviated considerably from the ideal characteristics expected for elastic tunneling through an ideal barrier. The data indicate that inelastic multistep tunneling as described by the Glazman-Matveev model is present. Our analysis indicates that the $SrTiO3$ barrier layer consists of two different parts: The interface region with the manganite electrodes containing a high density of structural defects, and the central barrier layer with a small density of defects. The observed temperature dependence of the junction resistance can be explained by a series connection of the resistance contributions from the interfacial and central barrier part. The magnetic field dependence of the junction resistance is found to depend strongly on the barrier thickness and can show complicated behavior due to both a complex magnetic state in the junction electrode and magnetic interactions between the ferromagnetic electrodes. A very large tunneling magnetoresistance up to $ΔR/Rp≃1200%$ is observed that, however, depends sensitively on the magnetic history.