(La_(1-x)Y_x)_(2/3)Ca_(1/3)MnO_3(x=0～0.3)体系的磁特性与平均稀土离子尺寸效应的研究  

STUDY OF MAGNETIC PROPERTIES AND ION SIZE EFFECT FOR (La_(1-x)Y_x)_(2/3)Ca_(1/3)MnO_3(0≤x≤0.3) MANGANESE

作　　者：张玉凤[1] 王新燕[1] 津幡健 曹桂新[1] 刘永生[1] 敬超[1] 西村克彦 森克德 曹世勋[1] 张金仓[1] 

机构地区：[1]上海大学物理系,上海200436 [2]富山大学工学部,日本富山930-8555

出　　处：《低温物理学报》2004年第1期1-7,共7页Low Temperature Physical Letters

基　　金：国家自然科学基金 (No .10 2 74 0 4 9);上海市教委科技发展基金 (No .0 1A16;No .0 2AK4 2 );上海市教委重点学科建设项目资助课题~~

摘　　要：研究了 (La1 -xYx) 2 / 3Ca1 / 3MnO3(0 .0≤x≤ 0 .3)体系的磁特性 ,给出了磁转变温度Tc 与La位平均离子尺寸之间的关联 .结果表明 ,随Y掺杂浓度的增加 ,金属 绝缘转变 (M I)温度TMI向低温区移动 ,对应的峰值电阻率 ρp 升高 ,对x =0 .3样品而言 ,较未替代样品 (x =0 .0 )增幅达 8个数量级之多 ,指出由于Y的掺入而致使La位平均离子半径 (<rA>)减少以及局域晶格结构畸变引起的 .磁性测量表明了在x >0 .1的高浓度区域 ,随着x的增加 ,反铁磁性相互作用逐渐增强 ,导致x =0 .2和x =0 .3的样品在 35K左右出现了自旋玻璃态 .The magnetic properties of perovskite (La 1-x Y x) 2/3 Ca 1/3 MnO 3 (0≤x≤0.3) compounds are systematically investigated and it is given that the transition temperature T c is related to average ion size of La site. It is found that with the increasing of Y 3+ doped content, the metal-insulator transition temperature T MI (M-I) shifts to lower temperature. While the relevant resistance peak ρ p sharply increases, for the sample of x= 0.3 , it has enhanced eight orders of magnitudes larger than the non-doped samples (x=0.0). The decrease of average ion size of La site and the local distortion of lattice constant due to the introduction of Y can explain the experimental results. At high concentration area, say when x>0.1, magnetic studies show a gradual increase of antiferromagnetic interaction with the increase of x, ultimately leading to a spin-glass-like state for x=0.2 and x=0.3 compounds at about 35K.

关 键 词：磁转变温度 离子尺寸效应 钙钛矿 钇掺杂 自旋玻璃态 磁电阻效应 铁磁材料 磁性 

分 类 号：O482[理学—固体物理]