Re-Entrant Spin-Glass Behavior of the Randomly Mixed Insulating Ferromagnet and Antiferromagnet, Rb₂Mn_(1−x)Cr_xCl₄

Abstract

An ac susceptibility measurement and a polarized neutron experiment have been performed on the random mixture, Rb₂Mn_(1−x)Cr_xCl₄ of an insulating ferromagnet Rb₂CrCl₄ and an insulating antiferromagnet Rb₂MnCl₄. The susceptibility of the mixed crystals rich in Cr atoms increases sharply at the Curie Temperature and then shows a drop-off at a lower temperature, indicating a double transition. The polarization of the neutron beam transmitted through the sample exhibits drastic changes at the two transition temperatures. The experimental results are interpreted by models recently proposed to explain re-entrant spin-glass transition.