On the thermal expansion of nanoparticles

Magnetite nanoparticles with an average particle size of 7.5 nm were studie d by Mossbauer spectroscopy in the 100-300 K temperature range. Using exper imental data on the temperature variation of isomer shifts in the partial s pectra of Fe-57 nuclei in the A and B crystal sublattices, the linear therm al expansion coefficient of the ultradisperse magnetite particles in the te mperature range studied was estimated within the framework of the molecular orbital formalism: alpha = (1.2 +/- 0.2) x 10(-4) K-1. (C) 2000 MAIK "Nauk a/Interperiodica".