Search for ferromagnetism in conductive Nb: SrTiO_3 with magnetic transition element (Cr, Co, Fe, Mn) dopants

摘要

Thin films of (0.5%, 1%) Nb:SrTiO_3 dilutely doped with (2 at. %) magnetic transition elements (Cr, Co, Fe, Mn) are examined for ferromagnetism. X-ray diffraction, Rutherford backscattering ion channeling, scanning transmission electron microscopy Z-contrast imaging, and electron energy loss spectroscopy techniques establish high crystalline quality of the films with no impurity phase(s) and highly uniform dopant distribution. Although the film conductivity improves dramatically by Nb doping, no ferromagnetism is found in any of our samples over the temperature range of 365 down to 5 K. This is contrasted to the case of ferromagnetism reported in cobalt doped (La,Sr)TiO_3.