La_(1-x)Ca_xMnO_3系列样品的低温比热  

LOW TEMPERATURE SPECIFIC HEAT OF La 1- x Ca x MnO 3

作　　者：王宇行[1] 王克勤[1] 曹烈兆[1] 周雅琴[2] 李可斌[3] 

机构地区：[1]中国科学技术大学物理系 [2]北京大学物理系 [3]中国科学院固体物理研究所

出　　处：《低温物理学报》1998年第1期45-50,共6页Low Temperature Physical Letters

基　　金：国家教委回国人员基金

摘　　要：我们系统地研究了Ｌａ１－ｘＣａｘＭｎＯ３多晶样品的低温比热，计算了相变时的比热跳跃和熵变，由此得出电子比热系数，并与自由电子比热系数和能带结构的计算结果进行了比较．我们认为电子关联作用和电子－声子相互作用对费米面态密度有较大的影响．同时我们发现Ｌａ０．８Ｃａ０．２ＭｎＯ３样品出现两个比热峰，这可能是由于两次磁相变造成的．AbstractWe have investigated the low temperature specific heat of La 1- x Ca x MnO 3( x =0.2,0.3,0.33,0.4,0.5 and 0.6)polycrystal samples. The specific heat jump and the entropy changing in the transition have been calculated. According to this, the electronic specific heat coefficient γ has also been calculated. Compared with the results of the free electron and the band structure calcultions, we find that γ is enhanced by the electron phone coupling and the electron electron interaction. We also find two specific heat anomaly in the La 0.8 Ca 0.2 MnO 3 sample, which may cause by two ferromagnetic transitions.

关 键 词：低温 比热 熵变 LCMO 超导体样品 磁相变 

分 类 号：TM262.014[一般工业技术—材料科学与工程]