Polaritons in modified antiferromagnets

Abstract

A theoretical study of mixed modes of uniaxial Heisenberg antiferromagnets by a dc field is presented. The static field is applied in an arbitrary direction relative to the easy axis and special attention is given to the magnetostatic limit where previous calculations show intriguing behavior of surface modes. Retarded polaritons are also considered and the spectrum that should be observed through the attenuated-total-reflection technique is calculated. Numerical results are presented for MnF2 and FeF2 semi-infinite specimens.