Nanocrystalline Ni0.8Zn0.2Fe2O4 films prepared by spray deposition from polyol-mediated sol: Microstructural and magnetic characterization

Autor: L. S. Smiri, Z. Beji, Fernand Fiévet, F. Herbst, Souad Ammar, Marie-Joseph Vaulay
Rok vydání: 2010
Předmět:
Zdroj: Thin Solid Films. 518:2592-2598
ISSN: 0040-6090
DOI: 10.1016/j.tsf.2009.07.188
Popis: Nanocrystalline films were directly prepared by spray deposition of a preformed polyol-based Ni 0.8 Zn 0.2 Fe 2 O 4 sol on a moderately heated glass substrate. The microstructural and magnetic properties of these films are investigated by X-ray diffraction, scanning electron microscopy and magnetic measurements on a Super Quanducting Interference Devices magnetometer. They are compared with those of nanoparticles precipitated from the sol, and with those of film subsequently annealed in air at 400 °C. The films and the powder exhibit superparamagnetic behaviour with a blocking temperature which increases from the powder to the as-produced film to the annealed film, in agreement with increasing stress and/or crystal size. They are ferrimagnetic at low temperature with a hysteresis feature strongly dependent on the synthesis conditions. The stresses induced in the film upon deposition undoubtedly correlate with a large grain boundaries volume which contributes to the H c , the coercitive field, increase and M sat , the saturation magnetization, decrease.
Databáze: OpenAIRE