Mössbauer Study of Some 2–17 Lanthanide-Iron Compounds

Abstract

We have studied the iron‐rich, rare‐earth‐iron intermetallic compounds R₂Fe₁₇ (R = Pr, Gd, Tm, Lu), using the Mössbauer effect in ⁵⁷Fe. The measured average hyperfine field H(T/T_c) acting on the ⁵⁷Fe nuclei is a unique, monotonically decreasing function of T/T_c, with no observed irregularity at temperatures corresponding to a suspected ferromagnetic‐antiferromagnetic phase transition in these compounds. The onset of paramagnetism occurs at temperatures close to the upper transition points measured by Strnat et al., namely at T_c = 282°, 472°, 271°, and 263°K for Pr₂Fe₁₇, Gd₂Fe₁₇, Tm₂Fe₁₇, and Lu₂Fe₁₇, respectively. Low‐temperature (≃90°K) spectra indicate the presence of at least four magnetically nonequivalent Fe sublattices, while for T>T_c broadened 2‐line absorption spectra typical of ⁵⁷Fe at noncubic sites in paramagnetic material are observed.