【摘要】 利用脉冲激光沉积(PLD)方法在多孔Al2O3模板上制备了纳米结构La0.67Ca0.33MnO3(LCMO)多晶膜.温度为80K时,LCMO纳米多晶环样品的电阻随时间连续下降,表现出明显的时效特征.时效后,样品具有保持低电阻状态的性质.该时效行为可用扩展的指数函数拟合.通过拟合可以得到相应条件下的样品平衡态电阻、样品的特征驰豫时间等信息.利用Core-Shell模型以及自旋玻璃相的存在对观察到的时效行为及拟合结果进行了解释.更多还原

【Abstract】 We prepared Nanostructured La₀.67 Ca₀.33 MnO₃ （LCMO） films by pulsed-laser deposition（PLD） on porous Al 2 O 3 substrates with an average thickness of 200nm. The temperature dependence of resistance was measured and the aging phenomenon of resistance was observed at 80K. The aging data can be well fitted using a stretched exponential function. From the fitted result, we can get the resistance corresponding to its stable state and the characteristic relaxation time at that temperature. The sample favors to keep the low resistance at that temperature after aging. Based on a Core-Shell model and the existence of spin-glass phase at the grain boundaries, we explained the observed resistance aging result and why our sample follows the stretched exponential law.更多还原