Structural, magnetic, and electronic properties of a GdAsSe single crystal: Experimental and theoretical studies

We report high-quality single-crystal growth, x-ray diffraction, magnetic susceptibility [χ(T,H)], magnetization [M(H)], heat capacity [CP(T,H)], electrical resistivity [ρ(T,H)], and electron spin resonance (ESR) measurements of GdAsSe as functions of temperature and magnetic field. We identify an antiferromagnetic phase transition at TN∼11.9±0.2 K and construct magnetic phase diagrams for H||ab and H||c axes based on the χ(T,H) and CP(T,H) data. Isothermal M(H) curves along the H||ab direction at 3 K exhibit a field-induced spin orientation at HC∼3.78T. Both M(H) and χ(T,H) indicate an easy-plane-type anisotropy. The Curie-Weiss analysis of the high-temperature paramagnetic χ(T) yields a negative Weiss temperature, suggesting dominant antiferromagnetic interactions between the Gd ions. Magnetic entropy reaches 83% of R ln8 at TN. The presence of residual entropy above TN and the persistence of ESR critical broadening up to ∼3TN alludes to a degree of magnetic frustration in the studied material. The ρ(T) data above TN is well fitted to the Bloch-Grüneisen theory for metals. Further, density functional theory calculations reveal an antiferromagnetic ground state where the Gd atoms are coupled ferromagnetically in the ab plane and antiferromagnetically along the c axis.