钙钛矿(La_(1-y)Tb_y)_(0-67)Sr_(0-33)MnO_3的磁致伸缩效应

MAGNETOSTRICTION OF (La_(1-y)Tb_y)_(0-67)Sr_(0-33)MnO_3 PEROVSKITE 

采用固相反应烧结法制备了（Ｌａ１ － ｙＴｂｙ）０－６７Ｓｒ０－３３ ＭｎＯ３ 系列样品（ ｙ ＝ ０ ，０－０５ ，０－１５ ，０－２０ ，０－２５ ，０－３３ ，０－４０ ，０－５０ ，０－６０ ，１－００） ．Ｘ 射线衍射表明，随着ｙ 值增大钙钛矿型晶体结构从菱面对称性向正交对称性转变．１８０ Ｋ 时，μ０ Ｈ＝ ７ Ｔ 条件下，在ｙ ＝ ０－４０ 样品的巨磁电阻可达９００ ％ ．μ０ Ｈ＝ １－７ Ｔ 时，ｙ ＝ ０－２０ 样品的室温磁致伸缩为－ ５０ ×１０ － ６ ．２１０ Ｋ 时，ｙ ＝０－３３ 样品的磁致伸缩可达－ １３０ ×１０ － ６ ．

A series of polycrystalline bulk samples of (La 1-y Tb y ) 0.67 Sr 0.33 MnO\-3( y= 0,0 05,0 15,0 20,0 25,0 33,0.40,0 50,0 60,1 00) have been prepared by solid\|phase reaction sintering. X\|ray diffraction patterns show that the rhombohedral structure has been transfered into orthorhombic structure with increasing Tb content y . For the sample with y= 0 40, a colossal magnetoresistance up to 900% has been observed at 180?K. When μ\-0H =1 7?T, the anisotropic magnetostriction ( λ \-t) of -50×10 -6 and volume magnetostriction ( ω ) -130×10 -6 have been observed for the samples of y =0.20 at room temperature, and y =0.33 at 210 K respectively.