Negative remanent magnetization of K 2 FeCl 5 ·H 2 O in small magnetic field

The remanent magnetization M r on easy-axis antiferromagnetic single crystal K2FeCl5·H2O is investigated. The sign of the remanent magnetization depends on the direction of the applied magnetic field H; if it is perpendicular to the easy axis of antiferromagnet then the sign of the remanent magnetization is positive, i.e. it coincides with the sign of the magnetic field in which the sample was cooled down below T N . Instead, if the magnetic field is directed along the easy axis then the sign of the remanent magnetization is negative and its absolute value is three orders of magnitude larger than usual magnetization M(T N , H).