The role of surface states in magnetic properties of nanocrystalline CuO

The temperature behavior of the magnetic susceptibility of a CuO low-dimens ional antiferromagnet subjected to spherically converging isentropic shock wave loading is investigated. The grain sizes in CuO polycrystalline sample s range from 5 to 110 nm. It is demonstrated that a decrease in the grain s ize leads to an increase in the role of the surface states in the magnetic properties. Unlike polycrystals prepared by standard methods, the susceptib ility of nanocrystalline samples in the range 78 K < T < 150 K decreases wi th an increase in temperature, which is explained by the formation of Cu2paramagnetic ions on the surface of nanocrystalline particles. (C) 2001 MAI K "Nauka/Interperiodica".