Abstract
The structure and magnetism of crystals with δ=0.060 and δ=0.020 were investigated by neutron scattering. is single-phase tetragonal (P/ncm) from 5 to 300 K with the onset of antiferromagnetic order appearing in the nickel sublattice at =116 K, as well as a gradual coupling of praseodymium spins appearing below 80 K. The ordered nickel moment at 10 K is estimated to be 0.62. Two coexisting phases are observed in the δ=0.020 sample, apparently resulting from phase separation. Above 118 K, one phase is orthorhombic (Pccn) and the other tetragonal (P/ncm), with =329 and 143 K, respectively. At 118 K, the orthorhombic phase undergoes a transition on cooling to tetragonal P/ncm symmetry. Spin structures and a magnetic transition are discussed in relation to octahedral distortions.
- Received 20 March 1990
DOI:https://doi.org/10.1103/PhysRevB.42.3944
©1990 American Physical Society