Formation, characterization and magnetic properties of maghemite gamma-Fe2O3 nanoparticles in borate glasses

摘要

A new type of nanocomposite materials based on maghemite, gamma- Fe2O3, nanoparticles dispersed in borate glasses co-doped with low contents of iron together with the larger radius element combinations: Y and Bi, or Sm and Pb, or Y and Pb is studied. Nanoparticles arise as a result of heat treatment of the glasses which gives them properties characteristic of magnetically ordered substances. Transmission electron microscopy and XRD show that only one magnetic phase, namely gamma-Fe2O3 nanoparticles, occurs in glasses subjected to the thermal treatment at 540 degrees C during 24 h independently on the doping element nature. At the same time doping element and their concentrations ratio in every combination affect the particles average size and glass magnetic properties, such as magnetization temperature dependences, Faraday rotation value and electron magnetic resonance spectrum characteristics. (C) 2014 Elsevier B.V. All rights reserved.