La_(0.7)Ca_(0.3)MnO_3多晶样品中的相分离研究  

Phase Separation Study of Polycrystalline La_(0.7)Ca_(0.3)MnO_3

作　　者：王芳[1] 

机构地区：[1]江苏科技大学数理学院,江苏镇江212003

出　　处：《材料科学与工程学报》2007年第5期785-787,774,共4页Journal of Materials Science and Engineering

摘　　要：采用固相反应法制备了La0.7Ca0.3MnO3多晶样品并借助X射线衍射,零场下的电阻测量以及电子顺磁共振技术对样品的结构、电子输运和磁性质进行了研究。实验结果表明,在居里温度TC附近,电子顺磁共振(ESR)谱线出现异常,谱线表现出明显的不对称,共振场随着温度的降低向低温方向移动。我们发现在居里温度TC以下用两个洛仑兹峰对ESR谱线可以进行较好的拟合,从而有力地证明了在相转变温度TC附近存在铁磁与顺磁相的共存。Polycrystalline La_(0.7)Ca_(0.3)MnO_3 was synthesized by a standard solid-state reaction method and its structure was studied.The electronic transport and magnetic properties were studied by X-ray diffraction,resistivity under zero magnetic field,and electron spin resonance(ESR) measurements.The ESR behavior of La_(0.7)Ca_(0.3)MnO_3 near T_C becomes abnormal,where linescape is asymmetric obviously and resonance field removes to low field with decreasing temperature.Two Lorentzian peaks can be used to well fit the ESR spectra near T_C,which powerfully evidence the coexistence of ferromagnetic phase and paramagnetic phase near T_C.

关 键 词：锰氧化物 超大磁电阻效应 电子顺磁共振 相分离 

分 类 号：O614.81[理学—无机化学]