Abstract
Neutron diffraction measurements confirm the presence of long-range antiferromagnetic order in superlattices of cobalt oxide and nickel oxide. A single transition temperature between the values for bulk CoO and NiO is evident for two samples with 36 Å periods as previously reported, but the separate Ni and Co order parameters in a 72 Å period superlattice approximate bulk behavior. In the latter sample the magnetic order remains coherent across ostensibly paramagnetic CoO interlayers above 400 K. Mean field analysis accounts for the layer thickness dependence of the ordering temperature.
- Received 25 June 1992
DOI:https://doi.org/10.1103/PhysRevLett.70.1878
©1993 American Physical Society