离轴磁场退火后Tb_(0.3)Dy_(0.7)Fe_(1.95)〈110〉取向晶体的磁致伸缩“跳跃”效应  

Magnetostriction-jump effect in〈110〉oriented Tb_(0.3)Dy_(0.7)Fe_(1.95) crystal after non-coaxial field annealing

作　　者：张昌盛[1] 马天宇[1] 严密[1] 

机构地区：[1]浙江大学材料科学与工程学系硅材料国家重点实验室,杭州310027

出　　处：《物理学报》2011年第3期677-682,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50701039);全国优秀博士学位论文作者专项资金(批准号:201037);中央高校基本科研业务费专项(批准号:2010QNA4004)资助的课题~~

摘　　要：将〈110〉取向Tb0.3Dy0.7Fe1.95合金棒放在与轴向成35°夹角的外磁场中退火处理,研究其在0—30MPa预压应力σpre作用下的磁致伸缩效应.结果表明,σpre=0条件下的饱和磁致伸缩值λs由退火前的1023×10-6提高到1650×10-6;σpre≤20MPa范围内,磁场退火后的样品均表现出显著的磁致伸缩"跳跃"效应,并且λs以及跳跃过程完成的磁致伸缩量λm都明显提高.当σpre=20MPa时,λs可达2315×10-6.此外,当σpre≤5MPa时,发生磁致伸缩"跳跃"效应的临界磁场Hjump也较未处理样品有所降低.通过分析磁致伸缩跳跃的临界场、非180°畴变的分布宽度等随σpre的变化规律,揭示了磁场退火前后样品磁化过程的差异.采用磁力显微镜观察了磁场退火前后的磁畴形貌,并探讨了磁场退火感生的各向异性对磁致伸缩性能的影响机理.An〈110〉oriented Tb0. 3 Dy0. 7 Fe1. 95 rod was annealed under a field of 0. 3 T,which was applied 35° away from its axis. Magnetostriction-jump effect of the magnetically annealed crystal was investigated under a series of uniaxial compressive pre-stresses ranging from 0 to 30 MPa. The magnetically annealed crystal possessed much higher saturation magnetostriction λs than the ones without applying any pre-stresses. When the compressive pre-stress was less than 20 MPa,the magnetically annealed specimen still exhibited obvious magnetostriction jump effect,possessing improved saturation magnetostriction λs and enhanced burst magnetostriction λm. A satisfactory magnetostriction as high as 2315 × 10^-6 could be obtained in the annealed crystal with the application of a pre-stress of 20 MPa. Furthermore,under a compressive pre-stress below 5 MPa,the critical field at which the magnetostriction-jump effect occurs also decreased, which was beneficial for low field applications. Difference in the magnetization processes caused by magnetic annealing was revealed through investigating the pre-stress dependences of the burst field Hjump and the distribution width of non-180° domain wall motion. Magnetic force microscopy images showed the changes of magnetic domain configurations induced by field annealing. Effects of the induced additional anisotropy on the magnetostrictive behaviors were also discussed.

关 键 词：磁致伸缩 磁场退火 磁致伸缩“跳跃”效应 

分 类 号：O482.526[理学—固体物理]