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通过机械合金化方法制备了单相Ｌａ０．７Ｃａ０ ．３ ＭｎＯ３ 化合物．球磨形成的非晶态结构在９２０Ｋ 退火时转变为钙钛矿型相结构．根据质量作用定律，讨论了非晶晶化动力学行为，其晶化转变激活能约为２６５ ｋＪ／ｍｏｌ．同时研究了化合物的电阻特性，发现低温下样品的电阻ρ与温度Ｔ 的关系为ρ∝Ｔ２ ，随退火温度的升高，ρＴ２ 曲线斜率下降．在远离居里温度处的低温磁电阻可用Δρ／ρ０ ＝ ｐ１ － ｐ２ Ｔ３／２ － ｐ３ Ｔ５／２ 描述．
Single phase La0.7Ca0 was prepared by mechanical alloying. 3 MnO3 compound. The non-crystalline structure formed by ball milling transformed to perovskite phase structure at 920K annealing. According to the law of mass action, the kinetics of amorphous crystallization is discussed. The activation energy of crystallization transition is about 265 kJ / mol. At the same time, the resistance characteristics of the compounds were studied. It was found that the relationship between the resistance ρ and the temperature T of the sample at low temperature is ραT2. With the increase of the annealing temperature, the slope of the ρT2 curve decreases. Low temperature magnetoresistance at temperatures far from the Curie temperature can be described as Δρ / ρ0 = p1 - p2 T3 / 2 - p3 T5 / 2.