The Study of Microscopic properties and Defects of Bi0.9Pb0.1FeO3/SrRuO3/SrTiO3 Bilayer Films

• Main Authors: Wei-Jhen Ciou, 邱韋禎
• Other Authors: Hsiung Chou
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/t63wn2

碩士 === 國立中山大學 === 物理學系研究所 === 106 === Multiferroic materials involve multiple couplings between electricity and magnetism. Especially for the magnetoelectric multiferroic materials that exhibit inherent coupling could be used as a mechanism to switch magnetic moment of an adjacent magnetic layer by applying an external electric field and vice-versa. BiFeO3 is a room temperature multiferroic material with a strong magnetoelectric coupling. When BiFeO3 is grown on SrTiO3 (100) substrates, its pseudo cubic structure provides eight degenerate electric polarizations. In addition, the leakage problem at domain walls causes great difficulty in control. Pb-doped Bi0.9Pb0.1FeO3(BPFO) and SrRuO3 bilayers along [111] direction were grown on atomically flat SrTiO3 (111) substrates by pulse laser deposition (PLD) technique. The doping of Pb helps to stop the electric leakage at domain walls, and the [111] orientation will simplify the polarization orientation switch states. By using a Piezoresponse Force Microscopy (PFM), we observed a very clean switch of electric polarization along [111] direction with no response on the in-plane direction. A charge accumulation phenomenon is observed that shifts the ferroelectric hysteresis loop similar to the magnetic exchange bias effect. Keywords: Multiferroic materials, ferromagnetic, SrTiO3, SrRuO3, Bi0.9Pb0.1FeO3