Random Fields and the Partially Paramagnetic State of CsCo 0.83Mg0.17Br3: Critical Scattering Study

The measurements of the critical neutron scattering on CsCo 0.83Mg0.17Br3, a dilute stacked triangular lattice (STL) Ising antiferromagnet (AF), were performed. In pure CsCoBr 3, a two component line shape associated with the critical fluctuations appeared at a temperature coincident with TN1. It was shown that such scattering is indicative of fluctuations in prototypical random field Ising model (RFIM) systems. The results show that magnetic vacancies nucleate AF domains in which the vacancies reside on the disordered sublattice thereby generating a RFIM state in the absence of an applied magnetic field.