~(57)FeHyperfine Parameters in Bi_(1-x)La_xFeO_3(x = 0 - 1)

摘要

hasbeen performed at room temperature (RT) to analyze influence of the space spin-modulatedmagnetic structure (SSMMS) on parameters of hyperfine interactions, the valence and magneticstates of iron ions. SSMMS in perovskites BiFeO_3and Bi0.9La0.1FeO_3leads to a specificdistribution of hyperfine fields P(H) with two peaks. Substitution La for Bi more than x = 0.2destroys SSMMS and P(H) corresponds to a distribution for a homogeneous spin structure.Concentration dependences of hyperfine fields (H), isomer (δ) and quadrupole (ε) shifts weremeasured. Due to the isomer shift values the iron ions are in the trivalent state. The local magneticmoments μ(Fe) on Fe~(+3)