Temperature Dependence of the Hyperfine Magnetic Field at Fe Sites in Ba-Doped BiFeO3 Thin Films Studied by Emission Mössbauer Spectroscopy

Emission 57Fe Mössbauer spectroscopy (eMS), following the implantation of radioactive 57Mn+ ions, has been used to study temperature dependence hyperfine magnetic field at Fe sites in Ba-doped BiFeO3 (BFO) thin films. 57Mn β decays (t1/2 = 90 s) 14.4 keV state 57Fe, thus allowing online eMS measurements a selection sample temperatures during Mn implantation. The were performed on two film BFO samples, 88 nm and 300 thick, doped 15% with Ba ions. samples prepared by pulsed laser deposition SrTiO3 substrates. X-ray diffraction analyses showed that films grew tetragonal distorted structure. spectra films, measured absorber range 301 K–700 K, comprised central pair paramagnetic doublets sextet feature wings. component was resolved into (i) attributed interactions Fe3+ ions located octahedral (Bhf); (ii) induced lattice defects, which characterized distribution BDistr. probes site room value Bhf 44.5(9) T. At higher temperatures, becomes much weaker, contribution disappearing above 700 K. Simultaneous analysis Ba–BFO shows variation follows Brillouin curve for S 5/2.