Magnetic behavior of nanosized cupric oxide

The effect of the particle size and ball-mill-induced defects on the magnet ic properties of cupric oxide has been assessed by magnetic measurements. N anoparticles with an average strain < epsilon > = 0.035 and average crystal lite size <D > = 9 mn show a susceptibility one order of magnitude higher t han the starting material. Up to room temperature, instead of the increasin g susceptibility found in bulk samples, a Curie-Weiss-like behavior is obse rved above the ordering temperature of ca. 230 K. (C) 2001 Elsevier Science B.V. All rights reserved.