Structural and physical properties of layered oxy-arsenides LnRuAsO (Ln = La, Nd, Sm, Gd)
arXiv:1207.2040 · doi:10.1016/j.jssc.2012.03.010
Abstract
Polycrystalline samples of LaRuAsO, NdRuAsO, SmRuAsO, and GdRuAsO have been synthesized and studied using powder x-ray diffraction, electrical transport, magnetization, and heat capacity measurements. Variations in structural properties across the series reveal a trend toward more ideal tetrahedral coordination around Ru as the size of the rare earth element is reduced. The lattice parameters of these Ru compounds show a more anisotropic response to variation in Ln than their Fe analogues, and significant anisotropy in thermal expansion is also observed. Transport measurements show metallic behavior, and carrier concentrations near 10^21 - 10^22 electrons per cm^3 are inferred from simple analysis of Hall effect measurements. Anomalies in resistivity, magnetization, and heat capacity indicate antiferromagnetic ordering of rare earth moments at 5 K for GdRuAsO, 4.5 K for SmRuAsO, and <2 K for NdRuAsO. Magnetization measurements on LaRuAsO show no evidence of a magnetic moment on Ru. Observed behaviors are compared to those reported for similar Fe and Ru compounds.
References in corpus (7)
- Structural and magnetic phase diagram of CeFeAsO1-xFx and its relationship to high-temperature superconductivity
- Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
- Influence of the rare-earth element on the effects of the structural and magnetic phase transitions in CeFeAsO, PrFeAsO, and NdFeAsO
- Superconductivity induced by ruthenium substitution in an iron arsenide: investigation of SrFe2-xRuxAs2 (0 <= x <= 2)
- Heat capacity measurements on FeAs-based compounds: a thermodynamic probe of electronic and magnetic states
- Structural trends from a consistent set of single-crystal data of REFeAsO (RE = La, Ce, Pr, Nd, Sm, Gd, and Tb)
- Suppression of spin density wave by isoelectronic substitution in PrFe(1-x)Ru(x)AsO