Elastic behaviour and internal friction studies on nanocrystalline Mn-Zn ferrite films prepared by the method of pulsed laser ablation

A laser ablation method was used for the preparation of nanocrystalline Mn-Zn ferrite thin films. Films were characterized using X-rays and TEM. The magnetic properties were measured using the vibrating sample magnetometer (VSM). The elastic behaviour and internal friction studies were carried out using composite piezoelectric oscillator method in the temperature range of 300-600 K. It was found that the value of Young's modulus decreases with an increase of temperature and shows anomalous behaviour in the vicinity of the Curie temperature. The internal friction for the present ferrites increases continuously with temperature up to the Curie point and a narrow peak was observed just below the Curie temperature. It was found that the anomalous behaviour observed in the temperature dependence of Young's modulus and internal friction disappears with the application of a magnetic field equal to the saturation field (900 mT) of the specimen under investigation. The observed anomalous behaviour in the vicinity of the Curie temperature was understood with the help of Landau's theory. (C) 2009 Elsevier B.V. All rights reserved.