Abstract
In spite of numerous experimental and theoretical reports on , no consistent picture has emerged of the nature of its ground state. We have investigated the system by means of muon-spin spectroscopy and susceptibility to gain further insight from the effects of varying the magnetic ion concentration. Static magnetic order, most likely to be incommensurate to the spatial lattice period, was found for at low temperatures , while disordered magnetism due to localized Ni moments appears for and, finally, exhibits almost fully nonmagnetic behavior down to the lowest measured. The ground state of is inferred to be a “static but short-range” -type antiferromagnetic ordered system, in which the moments align ferromagnetically along the axis in the plane with an incommensurate modulation probably due to canting of the moments, but align antiferromagnetically between adjacent planes.
3 More- Received 14 July 2008
DOI:https://doi.org/10.1103/PhysRevB.78.144412
©2008 American Physical Society