MAGNETIC PHASE-DIAGRAMS OF ALPHA-NIMOO4

In the antiferromagnetic ground state of alpha-NiMoO4 the magnetic mom ents within each sublattice are collinearly aligned in the ac-plane, b ut with a slightly different orientation for both sublattices. The mag netic phase diagrams have been determined for three different directio ns of the applied field, parallel to [0 1 0], [1 0 1] and within the a c-plane perpendicular to [1 0 1].The external fields, applied within t he ac-plane, induce two successive phase transitions, into a spin-flop phase first and into the forced ferromagnetic state second. In the sp in-flop phase the magnetic moments are aligned in the [0 1 0] directio n. A field parallel to [0 1 0] induces only one phase transition into the forced ferromagnetic state. (C) 1998 Elsevier Science B.V. All rig hts reserved.