Frustration and Random Fields in Triangular Lattice Antiferromagnets

B.D. Gaulin

Department of Physics and Astronomy, McMaster University

CsCoBr₃ and CsCo_1-xMg_xBr₃ are examples of pure and lightly diluted stacked triangular lattice antiferromagnets, respectively. Geometrical frustration manifests in these materials through the appearance of an unusual long range ordered state in CsCoBr₃: a three sublattice Neel state in which one of the sublattices is itself disordered. I will present critical neutron scattering measurements on diluted CsCo_1-xMg_xBr₃ which shows small concentrations of impurities to generate a very unusual state akin to the Random Field Ising domain state. Finally I will discuss the requirements of a diffuse scattering instument which can address this type of problem.