Ferroelectric And Ferromagnetic Properties Of Mn/Cu/Ba Co-doped LiNBO₃ Films

In this paper, the Mn/Cu, Cu/Ba and Ba/Mn co-doped LiNbO₃ films were deposited on SiO₂/Si?111?,La Ni O3/ Si?111?and quartz substrates by RF-magnetron sputtering technique. The structure and physical properties of LiNbO₃ films have been investigated systemically by XRD, XPS, SQUID, and U-V et al., the result are following:?1? XAFS, XPS and SQUID determined that the Mn/Cu co-doped films with Mn²⁺ repalcing Li and Cu²⁺ repalcing Nb exhibit room temperature ferromagnetism?RTFM?. 1.4 at% Cu-doped LiNbO₃ films having RTFM of 0.89 ?B/Cu can be described by BMP. 1.0 at% Mn-doped LiNbO₃ films having RTFM of 1.09 ?B/Mn attribute to the strong d-d electron interaction occurs between the Mn dopant and its neighboring Nb atoms. The decreasing AMM of Mn-doped LiNbO₃ thin films co-doped with Cu due to antiferromagnetic coupling between adjacent dopant atoms mediated by a central oxygen anion. The dielectric constant and dielectric loss of the Mn/Cu co-doped films decreases with the increase of doping concentration. The polarization and leakage current density of Mn/Cu co-doped film increases.?2?All Cu/Ba co-doped LiNbO₃ films with Cu²⁺ repalcing Nb and Ba²⁺ repalcing Nb exhibit RTFM. The saturation magnetization increasing with the dopant concentartion can be described by d⁰ ferromagnetism based on defects. Oxygen vacancy may be the main reason to RTFM. The dielectric constant and dielectric loss of the Cu/Ba co-doped films decreases with the increase of doping concentration.The polarization and leakage current density of Cu/Ba co-doped film decreases.?3?The Ba/Mn co-doped films with Mn²⁺ repalcing Li and Ba²⁺ repalcing Nb exhibit?RTFM?. Ba-doped film having RTFM can be described by d⁰ ferromagnetism. Mn-doped LiNbO₃ films having RTFM attribute to the strong d-d electron interaction occurs between the Mn dopant and its neighboring Nb atoms. The saturation magnetization of Ba/Mn co-doped films increases with the increasing doping concentration. The dielectric constant and dielectric loss of the Ba/Mn co-doped films decreases with the increase of doping concentration. The polarization and leakage current density of Ba/Mn co-doped film leakage current density increases.