X-ray Absorption Spectroscopy Studied of Sm0.67Sr0.33MnO3 Thin Films and Electronic Structure

• Main Authors: Chang, Pei-Yu, 張培裕
• Other Authors: 黃迪靖
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/21102441731002809439

碩士 === 國立交通大學 === 電子物理系所 === 104 === Sm1-xSrxMnO3 is a transition compound with a perovskite-type crystal structure. With different doping concentrations, Sm1-xSrxMnO3 exhibits various magnetic phase transitions and structural arrangement. Based on advanced epitaxial techniques, one can tailor the electronic structure of Sm0.67Sr0.33MnO3 which are epitaxially grown on a SrTiO3 (STO) substrate with different thickness. In this case, the strain from the substrates will influence the samples and distort the 3d orbital symmetry of manganese. Therefore, we not only conducted X-ray diffraction (XRD) experiment to confirm the crystal structure, but also the linear dichroism (LD) in soft X-ray absorption to investigate the electronic structure and orbital symmetry of the samples. Our results show that the z direction of 40-nm and 10-nm thin films are compressed. Furthermore, through X-ray absorption spectra and calculations, Mn3+ exists at the interface between substrates and thin films. The thinner the sample, the more Mn3+ contributes. In addition, Sm0.67Sr0.33MnO3 is ferromagnetic when the temperature is lower than the magnetic phase transition temperature. In this thesis, we used soft X-ray magnetic circular dichroism (XMCD) technique to compare difference between the bulk and the thin film samples and consequently found that the contribution of magnetism is thickness dependent.