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利用激光对半无限大物限加热的一维热传导模型,分析La0.67 Ca0.33 MnO3 (LCMO)薄膜在KrF准分子激光照射下的温度变化。在纳秒级激光单次脉冲照射下,薄膜表面温度与照射时间的平方根成正比。并通过拟合La0.67 Ca0.33 MnO3薄膜在此激光照射下的感生电压响应信号,得到薄膜的时间常数为1.39μs。利用薄薄厚度与时间常数的关系,计算出薄膜的热扩散系数及热穿透深度,分别为4.5×108m2/s和71nm。根据测量到的脉冲响应信号的时间常数,将激光感生电压公式中薄膜厚度与热扩散系数参量简化,得到一种求符向异性泽贝克(seeback)系数的方法,计算出出La0.67 Ca0.33 MnO3的各向异性泽贝克系数为2.80μV/K。
The temperature variation of La0.67 Ca0.33 MnO3 (LCMO) thin films irradiated by KrF excimer laser was analyzed by using laser one-dimensional heat conduction model. Under nanosecond laser single pulse irradiation, the film surface temperature is proportional to the square root of the irradiation time. By fitting the induced voltage response signal of La0.67Ca0.33MnO3 thin film under the laser irradiation, the time constant of the film is 1.39μs. Using the relationship between the thickness and the time constant, the thermal diffusivity and thermal penetration depth of the films were calculated, which were 4.5 × 108m2 / s and 71nm respectively. According to the measured time constant of the impulse response signal, the thin film thickness and thermal diffusivity parameters in the laser induced voltage formula are simplified, and a method of finding the seeback anisotropy coefficient is obtained, and the La0.67Ca0 .33 The anisotropic Zeebek coefficient of MnO3 is 2.80 [mu] V / K.