Gd_x((Fe_(83)Co_(17))_(55)Ag_(45))_(100-x)颗粒膜结构及巨磁电阻效应研究

Granular Film Structure and Giant Magnetoresistance Effect of Gd_x((Fe_(83)Co_(17))_(55)Ag_(45))_(100-x)

复合靶以Fe,Co,Ag和Gd按一定比例组成,采用磁控溅射法制备了Gdx((Fe83Co17)55Ag45)100-x(x=0,3.5,5.0,6.5,8.0,9.5)颗粒膜。在室温下,利用X射线衍射仪(XRD)、四探针电阻测试仪、振动样品磁强计(VSM)等方法研究Gd的掺入以及不同退火温度对颗粒膜显微结构、巨磁电阻效应(GMR)和磁性能影响。X射线衍射实验结果表明:薄膜形成了以Ag(111)和FeCo(110)组成的合金结构,且增加稀土Gd的掺入量能促进薄膜基体中FeCo与Ag的相分离。磁电阻测试结果发现:不同成分的Gdx((Fe83Co17)55Ag45)100-x(x=0,3.5,5.0,6.5,8.0,9.5)薄膜样品均随着退火温度升高以及稀土Gd含量增加,颗粒膜巨磁电阻(GMR)效应呈现先增后减的趋势,且饱和场逐渐降低,当x=5.0、退火温度250℃时,Gd5.0((Fe83Co17)55Ag45)95.0薄膜巨磁电阻效应达到最大,GMR值为-14.8%。Gd掺杂后样品磁滞回线的变化表明薄膜的矫顽力较小,矩形比随Gd含量的增加而增加,分析认为Gdx((Fe83Co17)55Ag45)100-x薄膜具有良好的软磁性能。

The target was composited with Fe, Co, Ag and Gd by a certain percentage, Gdx（Fe83Co17）55Ag45）100-x （ x = 0, 3.5, 5.0, 6.5, 8.0, 9.5） granular films were prepared by DC magnetron sputtering method. The influence of doping Gd and thermal an- healing on structure, giant magnetoresistance （GMR） and magnetic property of the films were studied by X-ray diffraction （XRD）, D. C. four-probe technique and vibrating sample magnetometer（VSM）. The XRD data indicated that the films formed an alloy structure with Ag（ 111 ） and FeCo（110）. Gd dement cou]d promote FeCo to dissdve in Ag to separate from Ag. GMR measurements indicated that GMR values of all films increased at first and then decreased with the increasing Gd content or annealing temperature, and the sat- uration field of GMR was gradually reduced. The maximum GMR value - 14.8% was obtained for Gd5.0（ （Fe83Co17）55Ag45 ）95.0 thin films annealed at 250 ℃ for 30 rain. Hysteresis loops of sample doped Gd indicated that the coercive of theGdx（Fe83Co17）55Ag45）100-x granular films was smaller, and the squareness ratio increased with the increase of Gd content. The granular films exhibited soft magnetic properties.