Structural, magnetic, and Mössbauer spectroscopic study of La³⁺ and Cu¹⁺ co-doped M-type strontium hexaferrite

Effects of La3+ and Cu1+ co-doping on the structural and the magnetic properties of M-type strontium hexaferrite have been studied by using crystallographic and magnetic measurements. Stoichiometric samples have been prepared by a conventional ceramic technique with repeated sintering at 1300 °C for 24 hours in the air. XPS Cu 2p scan shows that dominant valence state of Cu is +1. Analyses of the hysteresis curve reveals that MS increases and HC decreases with La-Cu content x. Room temperature Mössbauer spectral analysis indicates that Cu1+ preferentially replaces Fe3+ at 4 f2 site, which is consistent with the increase of MS with respect to the La3+-Cu1+ co-doping.