Magnetic and magnetotransport properties of epitaxial La_0.7Sr_0.3MnO₃/SrIrO₃/La_0.7Sr_0.3MnO₃ spin valves

We report on the fabrication of epitaxial La_0.7Sr_0.3MnO₃/SrIrO₃/La_0.7Sr_0.3MnO₃ (LSMO/SIO/LSMO) spin valve structures deposited on (0 0 1) (LaAlO₃)_0.3(Sr₂TaAlO₆)_0.7 substrates (LSAT) by high pressure sputtering. We present the structural, magnetic and magnetotransport properties of trilayers. Magnetization measurements indicate indirect exchange coupling between LSMO layers across the SrIrO₃ layer. An enhancement of saturation magnetic moment was observed for trilayers with one and six unit cell thick SrIrO₃ spacing layers. Low field magnetoresistance measurements show standard spin switching behavior and inverse spin switching in epitaxial LSMO/SIO/LSMO spin valve structures depending on the orientation of magnetic field to the plane and magnetic field to the current. (paper)