Field-dependent anomalies in the thermodynamic and transport properties of RuSr2GdCu2O8—Evidence for a spin-flop transition

Abstract Thermopower and magnetization studies of epitaxial thin films and sintered polycrystalline ceramics of RuSr 2 GdCu 2 O 8 show evidence for the occurrence of a spin-flop transition, consistent with earlier neutron diffraction data. Realignment of spins in a magnetic field enhances T c by up to 4 K, presumably due to reduced magnetic pair-breaking. Specific heat and powder AC susceptibility measurements give strong evidence for bulk superconductivity. High temperature magnetization measurements indicate in-plane ferromagnetic correlations which remain to be reconciled with low-temperature neutron diffraction evidence for conventional G-type antiferromagnetism.