Size-dependent magnetism and spin-glass behavior of amorphous NiO bulk, clusters, and nanocrystals: Experiments and first-principles calculations

A combined experimental and computational study was carried out to investigate magnetic properties of NiO nanostructures. Remarkable size-dependent magnetism was discovered. Uniform amorphous NiO showed a dominated antiferromagnetic interaction and an ordering temperature of 3.50.3em0exK. NiO clusters (up to 10.3em0exnm) tend to be ferromagnetic interaction with an ordering temperature of 350.3em0exK, accompanied by high magnetization (1050.3em0exemu∕g) and a spin-glass behavior. NiO nanocrystals (>20.3em0exnm) were found to be antiferromagnetic with uncompensated surface magnetization and shifted hysteresis due to the core-shell interactions.