【摘要】 采用固相烧结法和脉冲激光沉积法分别制备了钙态矿型锰氧化物Nd1-xSrxMnO3(x=0.1,0.2,0.3,0.4,0.5)大块多晶和Nd0.7Sr0.3MnO3在(100)LaAlO3基片上的单取向薄膜样品,分别研究了这些样品的磁电阻效应。研究表明,在多晶样品中,x=0.3时具有最大的磁电阻比,其值在240K和1T磁场下可达24.2%。对于同一成分的外延薄膜,发现磁电阻随着沉积时基片温度Ts的升高而下降,当Ts=500℃时的制备态薄膜在同样条件下的磁电阻可达84%,随着外加磁场增大到5T,磁电阻将线性增大到275%。并讨论了造成单取向膜和块材磁电阻不同的原因。更多还原

【Abstract】 The polycrystalline samples of Nd1xSrxMnO3 with x ranging from 0.1 to 0.5 and epitxial thin film of Nd0.7Sr0.3MnO3 were prepared by conversational solidstate reaction in air, and pulse laserdeposition (PLD) method, respectively. The colossal magnetoresistance effect of these samples was studied. The results indicate that in this series of polycrystalline samples, a maximum MR of ～24.2% is obtained under a magnetic field of 1 T at the temperature of 240 K for x=0.3. For epitaxial thin films with the same composition, it is found that their MR measured under the same condition has a maximum up to 84% at the deposition temperature of Ts =500 ℃ and decreases with increasing Ts. With increasing the applied field to 5 T, the MR of the film increases to 275% linearly at the temperature of 240 K. Finally, the possible reason causing the difference in MR between bulk materials and thin films was discussed.更多还原