Using half-metallic manganite interfaces to reveal insights into spintronics

A half-metal has been defined as a material with propagating electron states at the Fermi energy only for one of the two possible spin projections, and as such has been promoted as an interesting research direction for spin electronics. This review details recent advances on manganite thin film research within the field of spintronics, before presenting the structural, electronic and spin-polarized solid-state tunnelling transport studies that we have performed on heterostructures involving La_2/3Sr_1/3MnO ₃ thin films separated by SrTiO₃ barriers. These experiments demonstrate that, with a polarization of spin electrons at the Fermi level that can reach 99%, the La_2/3Sr_1/3MnO ₃/SrTiO₃ interface for all practical purposes exhibits half-metallic behaviour. We offer insight into the electronic structure of the interface, including the electronic symmetry of any remaining spin states at the Fermi level. Finally, we present experiments that use the experimental half-metallic property of manganites as tools to reveal novel features of spintronics.