La_(0.67)Ca_(0.33)Mn_(1-x)Cr_xO_3(0.0≤x≤0.15)中异常的CMR效应  

THE EXTRAORDINARY CMR EFFECT IN La_(0.67)Ca_(0.33) Mn_(1-x)Cr_xO_3 (0.0≤x≤0.15)

作　　者：刘宁[1] 孙勇[1] 童伟[1] 张裕恒 

机构地区：[1]中国科学技术大学结构分析开放实验室

出　　处：《低温物理学报》2001年第2期115-120,共6页Low Temperature Physical Letters

基　　金：国家自然科学重点基金;高等学校博士学科点专项科研基金

摘　　要：我们研究了Mn位掺Cr体系La0 .67Ca0 .33Mn1-xCrxO3( 0 .0≤x≤ 0 .15)的磁性和磁电阻性质 ,发现Cr掺杂对居里温度Tc 影响不明显 ,但是导致了反常的电输运和磁电阻行为 ,随着Cr含量的增加 ,起始电阻率峰向低温移动 ,同时电阻率出现一个附加峰 .在磁场作用下 ,两个电阻率峰被强烈压缩 ,导致CMR效应中出现双峰 ,并且CMR效应的温区被极大地拓宽 ,从低温直到接近室温 .这个结果表明 :Mn位元素替代是调节CMR效应的有效方法 .We have studied the magnetic and magnetotransport properties of Mn-site doped system La 0.67 Ca 0.33 Mn 1-x Cr xO 3 (0.0≤x≤0.15). It was found that the substitution with Cr on Mn sites is impotent in driving T c, but introduces extraordinary transport and CMR behavior. With increasing Cr content, an additional bump of resistivity grows up drastically while the original resistivity peak associated with magnetic order transition diminishes gradually. Under applied magnetic field, both bumps of resistivity are deeply compressed, which leads to the appearance of two peaks in CMR response. As a result, the temperature range of CMR response is significantly broadened, from the lowest to near room temperature. These results suggest that Mn-site element substitution could be a potent way in tuning CMR response.

关 键 词：La0.67Ca0.33Mn1-xCrxO3掺铬锰氯化物 巨磁阻效应 CMR 反常电输运 磁电阻 电阻率 低温物性 

分 类 号：O513[理学—低温物理] TM27[理学—物理]