Peculiarities of the exchange interaction in narrow-gap Hq_(1-x-y)Cd_xMn_ySe

摘要

The peculiarities of the exchange interaction between the carrierspin and localized spin moments of magnetic ions near thesemimetal-semiconductor transition have been studied in asemimagnetic quaternary solid solution system, Hg_(1-x-y)Cd_xMn_ySe(x = 0.10, y = 0.02, E_g = 45 meV), by means of Shubnikov-de Haasoscillations. The measurements show that the exchange ‘constant' αis actually a somewhat complicated function d of energy gap E_g andelectron concentration, which changes from negative values (αN_0=-0.15 eV) at lower electron concentration to positive values (αN_0= 0.28 eV) at higher electron concentration, values which are moretypically associated with wide-gap semimagnetic semiconductors.