The study of Mn doped BiFeO3 by RF magnetic sputtering

• Main Authors: Chih-an Lin, 林志安
• Other Authors: Xiaoding Qi
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/03591514725897348116

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 96 === BiFeO3(BFO) is one of the most potential multiferroic materials for new device applications. This is because BFO has high ferroelectric Curie temperature (850oC) and antiferromagnetic Neil temperature (370oC), which are both above room temperature. This research mainly investigated the effects of manganese doping, i.e. BiFe1-XMnXO3 x = 0, 0.1, 0.2, 0.3, 0.4, on the BFO properties. Because BiMnO3 (BMO) is a ferroelectric ferromagnet and also, Mn3 + ion has a similar radius to Fe3 + ion, it was expected to be able to replace some Fe3 + with Mn3 +, resulting in new magnetic properties in the mixed compound BiFe1-XMnXO3 (BFMO). This experiment utilized RF magnetic sputtering to deposit films on the Si, SrTiO3 and LaAlO3 substrates at room temperature, which were subsequently sintered at high temperatures to form the desired phase. X-rays diffraction (XRD) was used to analyze the phase purity and structures of the prepared films, X-ray photoelectron spectroscopy (XPS) was used to study the ion bonding valence, field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) was used to observe the surface morphology of the films, and finally superconducting quantum interference device (SQUID) was used to measure the magnetization-magnetic field (M-H) hysteresis loops in order to understand the magnetic properties of the films. We found that more impurity phases appeared with more addition of Mn, indicating that there was a limit for Mn doping in BFO. By the XPS analysis, it was shown that with the increased amount of Mn doping, the grain size of films became smaller . AFM showed that the more Mn addition, the rougher of the surface. It was also found by SQUID measurement that with the addition of Mn (x=0.1) , there was an increase of the saturated magnetization of the doped films.