Magnetization reversal in weak ferrimagnets and canted antiferromagnets

In some ferrimagnets the total magnetization vanishes at a certain compensation temperature T*. In weak magnetic fields, the magnetization can change sign at T* (the magnetization reversal). Much rarer is observation of ferrimagnetic-like response in canted anti ferromagnets, where the weak ferromagnetic moment is due to the tilting of the sublattice magnetizations. The latter phenomenon was observed in nickel (II) formate dihydrate Ni(HCOO)(2). 2H(2)O. The observed weak magnetic moment increases initially below T-N = 15.5 K, equals zero at T* = 8.5 K and increases again at lowering temperature. The sign of the low-field magnetization at any given temperature is determined by the sample's magnetic prehistory and the signs are opposite to each other at T < T* and T* < T < T-N. (C) 2003 Elsevier Science B.V. All rights reserved.