Preparation of Bi substituted yttrium orthoferrite nanopowders by sol- gel method and investigation of their magnetic properties

Abstract

Nanopowders of Y1-xBixFeO3 (x=0.0, 0.1, 0.15 and 0.2) have been synthesized by the sol gel method. Xray diffraction identifications show that all the samples have orthorhombic structure and mean crystallite sizes of the nanopowders are in the range of 40 nm, using Scherrer's formula. Mean particle sizes of the samples were obtained by TEM, which is in the range of 75 nm. The 57Fe Mössbauer spectra of Y1-xBixFeO3 nanopowders at 78 and 295 K have been recorded and the results show that all the Fe3+ ions are almost at the symmetrical positions. Room temperature magnetization measurements show that with increasing Bi content up to 0.15, the magnetization increases, whereas it decreases for the sample with x=0.2. M-T curves of the samples were recorded at applied fields of 40 and 13500 Oe. Although all samples show a metamagnetic behavior around Tk=225 °C and at higher applied field, but for the sample with x=0.2, the behavior is more clear.