La_(0.7)Ca_(0.3)MnO_3多晶陶瓷相变行为的力学研究

A MECHANICAL INVESTIGATION ON THE PHASE TRANSITION BEHAVIOR OF La_(0.7)Ca_(0.3)MnO_3 POLYCRYSTALLINE CERAMICS

对 L a0 .7Ca0 .3Mn O3多晶陶瓷样品进行了力学性能和热学性能研究 .内耗测量结果表明 ,样品在 Tc附近存在一个尖锐的损耗峰 ,该峰与材料的铁磁顺磁相变有关 .差示扫描量热分析结果也显示样品在居里温度附近存在一吸热峰 .在升温和降温过程中 ,该内耗峰出现较大的热滞后及铁磁相变 ,并伴有一定的相变潜热 ,表明 La0 .7Ca0 .3Mn

A mechanical and thermal study on polycrystalline La 0.7 Ca 0.3 MnO 3 is performed. The results show that a sharp peak of the internal friction and a considerable frequency drop of the sample can be associated with a ferromagnetic\|to\|paramagnetic phase transition which is also accompanied by an absorption peak found by DSC. A first\|order type magnetic phase transition is observed for the polycrystalline La 0.7 Ca 0.3 MnO 3 system.