AFMR in KMnF3 near TN and TC; New experimental results
Acta Physica Polonica, Vol. A54, No.4, 397-409 (1978).
The AFMR (antiferromagnetic resonance) spectra of carefully prepared KMnF3 single crystals have been measured with high temperature resolution near the Neel (TN) and Curie (TC) temperatures. The results allow several important conclusions: a KMnF3 crystal undergoes structure inversion at temperature Tx = TN – 0.5°K, from tetragonal with c/a > 1 to tetragonal with c/a < 1; the first-order structural phase transition at Ts = 81°K strongly depends on the size of cristallites or crystallographic domains; the Curie temperature TC cannot be identified with this temperature Ts.