Fe,Sn掺杂In2O3薄膜室温铁磁性的电场调控

Fe,Sn doped In2O3 films will be prepared by pulsed laser deposition (PLD) and laser molecular beam epitaxy (L-MBE) techniques. By optimizing the experimental parameters and techniques,the noncompensated p-n pairs of Fe-Sn will be used to obtain the almost homogeneous films, in which the Fe and Sn both incorporate into the indium oxide lattice by substituting the position of indium atoms. By applying external electric fields on a metal-insulator-semiconductor structure, the Hall effect, the magnetic-field dependence of Hall resistance and the hysteresis loops of the Fe,Sn doped In2O3 films will be measured. We will investigate the effect of the gate voltage on the carrier density, mobility, anomalous Hall conductivity, magnetization and Curie temperature of the films. The different insulator materials will be choosed to study their influences on the gate voltage. The room temperature ferromagnetism of Fe,Sn doped In2O3 films will be turned "On" and "Off" by the external electric fields. The results to be obtained from this proposal will be very helpful for future application of oxide diluted magnetic semiconductors in spintronics devices.

采用脉冲激光沉积和激光分子束外延技术，以Fe/Sn为非补偿性p-n对，通过优化实验方案，制备出由Fe和Sn取代In的均相In2O3薄膜。设计"金属-绝缘体-半导体"结构单元，在外加电场下，测量其霍尔效应、霍尔电阻随外磁场的变化曲线以及磁滞回线。研究外加电场对Fe,Sn掺杂In2O3薄膜的载流子浓度、霍尔迁移率、反常霍尔电导率、磁化强度和居里温度的影响；选择不同介电常数的绝缘层材料，研究其对外加电压的影响。在较小的外加电压下实现对Fe,Sn掺杂In2O3薄膜室温磁性"开"与"关"的电场调控。该项目的研究将为氧化物稀磁半导体在未来自旋电子器件的应用提供一定的实验依据。

目前，采用合理的制备技术和方法制备出均相的氧化物稀磁半导体薄膜，是其在自旋电子学器件中应用的关键问题。针对这一问题，在本项目的研究中我们利用脉冲激光沉积技术，以Fe/Sn为p-n对，采用非补偿p-n共掺杂的方法制备出了均相的Fe/Sn共掺杂In2O3薄膜，对其结构、磁性和输运性质进行了研究。为了进一步证实这种方法的可行性，我们还制备了Fe/Cu共掺杂In2O3稀磁半导体薄膜，研究发现Fe/Cu共掺杂In2O3薄膜中有金属Fe存在，Fe-Cu无法形成非补偿p-n对，薄膜的结构和铁磁性都是不均匀。采用脉冲激光沉积技术制备了与In2O3相关的La0.7Ca0.3MnO3/In2O3异质结薄膜，研究发现在La0.7Ca0.3MnO3和In2O3异质结之间沉积Fe纳米点后，能显著提高La0.7Ca0.3MnO3的居里温度和金属-绝缘体转变温度。我们还利用脉冲激光沉积、磁控溅射和氩离子刻蚀等技术相结合，制备了以(In0.93Fe0.05Sn0.02)2O3薄膜和Ti0.98Co0.02O2薄膜为半导体的“金属-绝缘体-半导体”结构单元，通过外加电场研究了其磁性和输运性质。项目的研究成果对于氧化物稀磁半导体薄膜在自旋电子学器件中的应用提供一定的实验依据。