Effect of antiferromagnetic ordering on the optical transitions in MnF 2

Abstract

Two optical absorption bands (viz. C and F) in MnF 2, whose line positions are nearly temperature-independent above T N = 67.3 K, are investigated for the effect of magnetic ordering. Both bands are blue-shifted by Δ E (≌90 cm −1 for C and 120 cm −1 for F at 10 K) and the lines show additional narrowing on cooling through T N . It is found that Δ E varies as the sublattice lattice magnetization below T N and nearly as the magnetic energy above T N .