La_(0.67)Ba_(0.33)Mn_(1–x)Zn_xO_3的磁性和电输运性质  

MAGNETISM AND TRANSPORT PROPERTIES OF La_(0.67)Ba_(0.33)Mn_(1–x)Zn_xO_3

作　　者：王玉[1] 杨海涛[1] 陈冬[1] 黄丽[1] 何军辉[1] 

机构地区：[1]扬州大学物理科学与技术学院,江苏扬州225002

出　　处：《低温物理学报》2013年第6期413-418,共6页Low Temperature Physical Letters

基　　金：国家自然科学基金(批准号:10974170)资助的课题~~

摘　　要：采用传统固相反应法制备了La0.67Ba0.33Mn1–x Znx O3(0≤x≤0.2)多晶样品,系统研究了Zn掺杂对于多晶样品的结构,磁性和电输运性质的影响.XRD衍射表明样品均具有单一的立方钙钛矿结构.在外加磁场(H=1000Oe)环境中测得的磁化强度温度(M^T)曲线表明,在5~350K的温区内所有样品均发生了顺磁相(PM)到铁磁相(FM)的转变.样品的居里温度(TC)和磁化强度随着Zn的掺杂量的增加呈现下降的趋势,当x=0.1时,样品的TC和磁化强度与未掺杂的样品相比下降的幅度不大.但是当x=0.2时,样品的TC和磁化强度都发生明显的下降.从零场(H=0T)和外加磁场(H=2T)下测得的电阻温度曲线可见,样品在测量的温区范围内均发生绝缘相到金属相的转变.随着掺杂量的增加绝缘-金属相转变温度(TIM)向低温区移动,但是样品的电阻逐渐增大.所有样品在TIM附近呈现均出现磁电阻(MR)峰,随着Zn的掺杂量的增加MR值由x=0时的-22%(T=314.5K)增加到x=0.2时的-73%(T=80K),且样品的磁电阻温区被明显拓宽.The Zn-doping La0.67Ba0.33Mn1-xZnxO3 （0≤x≤0. 2）samples have been prepared by conventional solid- state reaction method. We have systematacially investigated the influence of Zn-doping on the structure, transport properties and magnetoresistance. The X-ray diffraction results revealed that all the samples exhibits simple cubic perovskite structure at room temperature. The M~ T curves for zero filed-cooled（ZFC）condition in a magnetic filed of 1000Oe suggests that with the increase of the temperature all the samples exhibit a ferromagnetic to paramagnetic phase transition. The Curie temperature and the intensity of magnetization are found to decrease upon Zn doping. Compared with un-doping samples, when x = 0. 1 the Curie temperature and intensity of magnetization of all the sam- pies have no obvious change but when x= 0. 2 the Curie temperature and intensity of magnetization experience a re- markable decrease. The temperature dependence of resistance curves are measured under H=OT and H=2T, which reveals a metal-insulator transition, with the substitution of Zn the Tc move to low temperature zone, but the re-sistance of all the samples increase gradually. All samples around Tc appear a peak of MR, the value of MR increa- ses from - 22 %（x= 0. 0） to - 73 % （x= 0. 2）. With the increasing of doping amounts, the temperature zone of MR has been widened.

关 键 词：Zn掺杂 磁电阻 锰氧化物钙钛矿 磁性 

分 类 号：O484.43[理学—固体物理]