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采用射频磁控溅射方法在LaAlO3(100)基片上制备了电荷有序态锰氧化物Sm0.5Ca0.5MnO3薄膜,X射线衍射分析表明所制备薄膜具有较好的外延特性。测试了薄膜的低电阻-温度关系,表明薄膜在测量温度范围内呈现半导体导电特性。施加磁场和激光辐照均可引起电荷有序态的退局域化,从而导致电阻减小。研究了激光诱导电阻变化弛豫特性,表明电阻随时间的变化符合指数关系,通过拟合得到的时间常数随着温度的升高而增加,分析表明其主要可归结于外在热效应的影响。
The charge-ordered manganese oxide Sm0.5Ca0.5MnO3 thin films were prepared on LaAlO3 (100) substrate by RF magnetron sputtering. The X-ray diffraction analysis showed that the prepared thin films have good epitaxial properties. The low resistance-temperature relationship of the films was tested, indicating that the films exhibit semiconducting properties over the measurement temperature range. Both the application of a magnetic field and laser irradiation can cause the deregulation of the charge-ordered state, resulting in a decrease in resistance. The relaxation characteristics of laser-induced resistance change were studied. The results show that the change of resistance with time is in accordance with the exponential relationship. The time constant increases with the increase of temperature. The analysis shows that it is mainly due to the external thermal effect.