TbDyFe/Fe多层膜磁致伸缩及其与压电衬底的磁—电转换性能研究

【作者】 李再轲；

【导师】 斯永敏；

【作者基本信息】 中国人民解放军国防科学技术大学 ， 材料物理与化学， 2002， 硕士

【摘要】 本文对用直流磁控溅射工艺制备的Fe薄膜、TbDyFe薄膜以及TbDyFe／Fe多层膜的磁性能进行了研究，着重分析了它们的磁致伸缩性能，并研究了由驰豫型铁电陶瓷PMN-PT为衬底，由磁致伸缩薄膜和Fe薄膜作电极构成的样品的磁—电转换效能。 利用SEM、XRD等对薄膜的结构和表面形貌进行分析。结果表明：制备态的纯Fe薄膜为α-Fe晶态结构，单一TbDyFe薄膜为非晶态，450℃以下真空退火20分钟对单一薄膜的结构没有明显影响；在制备态，TbDyFe／Fe多层膜的结构为单一Fe薄膜和单一TbDyFe薄膜的叠加，但对温度变化非常敏感，经250℃真空退火20分钟，多层膜即被氧化，随着退火温度的升高氧化加剧。 对薄膜的磁性能研究发现：单一TbDyFe薄膜的易磁化方向垂直于膜面，而TbDyFe／Fe多层膜与单一Fe薄膜的易磁化方向皆平行于膜面；Fe层薄膜的加入，使多层膜的饱和磁化强度升高，剩磁比增大，矫顽力和饱和磁场降低；随着退火温度的升高，多层膜的易磁化方向向垂直于膜面的方向移动，磁化机制由形核类模型向钉扎类模型转变。 对单一TbDyFe薄膜和TbDyFe／Fe多层膜的磁致伸缩性能对比发现：多层膜的饱和磁致伸缩性能高于单一薄膜的磁致伸缩性能，80KA／m以下的磁致伸缩性能提升更为明显。多层膜的磁致伸缩性能与Fe层的厚度有关。在铁磁交换距离以内，薄膜的磁致伸缩值随着Fe层厚度的降低而升高。低温退火有助于磁致伸缩性能的提高，退火温度超过450℃时，由于薄膜氧化严重，磁致伸缩性能下降。 对超磁致伸缩薄膜／压电陶瓷基片的磁-电转换性能的研究表明，输出电压与基片面积大小有关，在静磁场作用下，长片状基片面积越大，输出电压越大。输出电压还与磁致伸缩薄膜的磁致伸缩系数有关，磁致伸缩系数越大输出电压越大。更多还原

【Abstract】 The properties of Fe, TbDyFe films and TbDyFe/Fe multilayers prepared by DC magnetron sputtring were investigated in this paper. The purpose was to find a way to improve the magnetostriction of the TbDyFe films,especially in low magnetic field. The magnetic-mechanical-electrical translation effect of the films,which were sputtered on the PMN-PT piezoelectric base, was also studied .Microstructure of the films was analyzed by SEM and XRD.The results showed that the single Fe films were in the form of α-Fe while TbDyFe films were amorphous.The microstructure of the multilayers was made up of α-Fe and TbDyFe amorphous. The microstructure of the single Fe and TbDyFe monolayers had changed little after they were annealed below 450℃,but that of the multilayers were sensitive to the annealing temperature. They were oxidized after annealed at even 250℃.The investigation on the films’ magnetic properties revealed that the easy axis of the single TbDyFe films were vertical to the surface,while that of the Fe monolayers and TbDyFe/Fe multilayers were parallel to the surface .Both Ms and Mr/Ms increased while the He and Hs decreased as a result of the addition of the soft magnetic Fe films.The easy axis moved from the films surface to the vertical location with the increase of multilayers’ annealing temperature. The mechanism of magnetization were changed from magnetic nuclear forming to domain wall nailing.The saturated magnetostriction of the multilayers were superior to that of the TbDyFe monolayers,especially in low magnetic field.Moreover,the magnetostriction of the multilayers increased sharply with the decrease of the Fe films’ thichness when they were within the length of exchange coupling.The same phenomena has discoverd when annealed under 250℃,but the contrary results had because of the oxidation when the temperature over 450℃.The research on the magnetic-electric translation effect of TbDyFe/PMN-PT and (TbDyFe/Fe)/PMN-PT indicated that the output poling voltage was relation to the PMN-PT’s width and the films’ magnetostriction. The more wider the base’s width and themagnetostriction were , the higher the output voltage in the static electric field was.更多还原