Oxygen nonstoichiometry and magnetic properties of doped manganites La0.7Sr0.3Mn0.95Fe0.05O3-δ

In this work, solid solutions of La 0.7 Sr 0.3 Mn 0.9 5Fe 0.05 O 3-δ with different oxygen content were obtained by the solid-phase reactions technique. Based on investigation dynamics changes in index (3 – δ) during heating samples, formation a stressed state their grains as result annealing was established. This results decrease mobility vacancies reduction cations according to 4+ + e → 3+ scheme and explains released amount an increase δ well rate samples. When studying magnetic properties it found that temperature dependence magnetization obeys Curie–Weiss law defficiency increases, Curie for decreases. It particles are frozen ferromagnetic when measured low-temperature region М ( Т ) “zero-field mode” at ˂ В . The presence ferromagnetism ˃ leads magnetically ordered state, which resulting moment particle is influenced thermal fluctuations. considering values lanthanum-strontium manganite region, ordering disturbed due excitation magnons quadratic energy from wave vector, number increases proportion T 3/2 magnetization. observed “field-cooling approximated taking into account non-quadratic dispersion laws magnon spectrum.