Giant Low-Field Magnetoresistance in Polycrystalline La_(2/3)Ca_(1/3)Mn_(1-x)Cu_x O_3 Sintered at 1

• 作 者: 杨应平 袁松柳 刘洁 张国庆 夏正才
• 机 构: Department of Physics,Huazhong University of Science and Technology, Wuhan 430074, China, Departmen
• 出 处: Journal of Rare Earths
• 发表日期: 2004年03期
• 关键词: Giant Ca La Mn tempera insulator alloyed

The La_(2/3)Ca_(1/3)Mn_(1- x )Cu_ x O_3 (0≤ x <6%) samples were prepared by sol-gel method. Transport properties, conductive mechanism and low-field magnetoresistance ( MR _0) were investigated. It is found that conductive mechanism is described by Mott′s variable-range hopping and the MR _0 near the insulator-metal transition temperature ( T _p) increases from 2% to 80% with x from 0 to 4% for a low field of 0.3 T. The experiment also shows that the intergrain magnetoresistance is largely improved. The results indicate that a proper amount of Cu doping can substantially improve magnetoresistance effects.

The La_ (2/3) Ca_ (1/3) Mn_ (1- x) Cu_xO_3 (0≤x <6%) samples were prepared by sol- gel method. Transport properties, conductive mechanism and low-field magnetoresistance MR_0) were investigated. It is found that conductive mechanism is described by Mott’s variable-range hopping and the MR_0 near the insulator-metal transition temperature (T _p) increases from 2% to 80% with x from 0 to 4 % for a low field of 0.3 T. The experiment also shows that the intergrain magnetoresistance is substantially improved. The results indicate that a proper amount of Cu doping can improve performance of magnetoresistance effects.