Mössbauer Study of Magnetic Ordering in a Triangular Spin System: RFeMO₄

Abstract

Mössbauer spectra of ⁵⁷Fe in RFeMO₄, a family of triangular antiferromagnets, were observed below 300 K, mainly at 4.2 K. For the compounds of M=Mn or Co, it was concluded from the spectra at 4.2 K that the axis of the electron spin of Fe³⁺ is not determined as related with the crystal lattice but distributes homogeneously. The spin state was discussed briefly in connection with the recent theoretical work on the antiferromagnetic triangular lattice.