Neutron-powder-diffraction study of the structure and antiferromagnetic ordering inPr2CuO4

Abstract

A neutron-powder-diffraction study has been carried out on ${\mathrm{Pr}}_2$ ${\mathrm{CuO}}_4$, which has the T’-type structure of the new high-$T_c$ electron superconductors. The compound orders antiferromagnetically at about 270 K. The magnetic intensities at 15 K can be equally well accounted for by a collinear magnetic structure with orthorhombic symmetry or a noncollinear structure with tetragonal symmetry. In both cases, Cu moments are coupled antiferromagnetically within the ${\mathrm{CuO}}_2$ layers, the ordered moment being 0.48${\mu }_B$ at 15 K. Rietveld refinement at 298 and 15 K shows the crystal structure is essentially unchanged; in particular, there is no detectable distortion at low temperature.