EXCHANGE AND SUPER-LATTICE BAND SPLITTINGS IN EUROPIUM CHALCOGENIDES - MAGNETO-OPTICAL STUDY IN HIGH MAGNETIC-FIELDS

The impact of high magnetic field studies on the understanding of the interaction between electronic structure and magnetic order is discussed for the europium chalcogenides. Faraday rotation measurements on EuTe for H {less-than or greater-than} Hc ≈ 70 kOe confirm the occurrence of a superlattice splitting of the empty conduction band in the antiferromagnetic phase. The red shift of the absorption edge of EuTe is determined to be 110 meV for magnetic saturation. The striking change in the absorption spectrum of EuS near saturation is discussed in the framework of a recent quasiparticle multi-band theory. © 1979.