Spin fluctuations in a random magnet with competing anisotropies: Fe0.75Co0.25Br2

Abstract We have performed neutron scattering experiments on Fe 0.75 Co 0.25 Br 2 , a random magnet with competing spin anisotropies. We observe short-range correlations in the spin components both parallel and perpendicular to the c axis, in addition to the antiferromagnetic long range order with T N ≈ 11 K. The scattering from the perpendicular spin components shows broad incommensurate peaks below 13 K.