Off-diagonal exchange-induced transverse and field-induced spin-flop order in the diluted metamagnet Fe_0.85Mg_0.15Br₂

Authors

Wolfgang Kleeman, Laboratorium f¨ur Angewandte Physik, Gerhard-Mercator-Universit¨atFollow
H. Aruga Katori, RIKEN (The Institute of Physical and Chemical Research)
T. Kato, Chiba University, Japan
Christian Binek, University of Nebraska-LincolnFollow
K. Katsumata, RIKEN (The Institute of Physical and Chemical Research)

Date of this Version

9-1-2001

Comments

Published by EDP SCiences. Copyright 2001. Permission to use. Europhys. Lett. 55, 732 (2001).

Abstract

Specific heat and Faraday rotation magnetometry were used to determine the axial magnetic phase diagram of the dilute hexagonal antiferromagnet Fe_0.85Mg_0.15Br₂. In contrast to metamagnetic pure FeBr₂, the first-order line of transverse phase transitions, H1(T), is disconnected with the antiferro-to-paramagnetic phase line H_c(T) and extends down to H_t=0 at T_t≈8.7 . This is attributed to symmetric off-diagonal exchange in the presence of structural disorder. Moreover, a spin-flop phase emerges beyond H_c(T) up to a bicritical point (T_b≈9.3 , μ_oH_b≈1.3 ).