离子注入NiFeCo/Ag颗粒膜巨磁电阻效应的研究

【作者】 温伟祥；

【导师】 胡社军； 黄拿灿；

【作者基本信息】 广东工业大学 ， 材料加工工程， 2001， 硕士

【摘要】 本论文用直流磁控溅射技术制备了零磁致伸缩三元合金NiFeCo和非磁性金属Ag组成的颗粒膜，研究了离子注入、磁性组分、退火温度对NiFeCo/Ag颗粒膜巨磁电阻效应和磁性的影响；用四探针法和振动样品磁强计分别对薄膜的巨磁电阻效应和磁性进行测试；用X-射线衍射对颗粒膜晶体结构进行分析；用卢瑟福背散射对薄膜成分进行分析；用场发射电镜、原子力显微镜和磁力显微镜分别对薄膜表面和截面形貌及磁畴结构进行观测。研究表明： 自行设计制造且具有特殊磁场分布的RFMS—4溅射仪制备颗粒膜和多层膜工艺技术稳定可靠，在优化工艺条件下能保证薄膜成分与溅射速率的稳定性。 未经离子注入的NiFeCo/Ag颗粒膜最佳退火温度为300℃，最佳磁性相原子百分比为36％，室温下获得的最佳巨磁电阻值为5％（饱和场为7.6KOe），4.2K下获得巨磁电阻效应最大值为19％。 NiFeCo/Ag颗粒膜经Fe离子注入后，未经退火即有2.3％的巨磁电阻效应，室温下最大巨磁电阻效应为9％（饱和场为10KOe）。而经Co离子注入后，未经退火即有巨磁电阻值5.5％，室温下最大巨磁电阻效应高达9.8％，这是迄今国际上用离子注入技术制备巨磁电阻薄膜获得的最佳结果。 注入Co离子对颗粒膜巨磁电阻效应增大的贡献超过注入Fe离子，在较低温度下退火尤其明显。 注入Fe、Co离子后，颗粒膜最佳磁性组分没有变化，但最佳退火温度变为360℃。离子注入后的颗粒膜存在一个临界增强扩散退火温度。当退火温度超过此温度后，增强扩散效应更加明显，磁性相与非磁性相分高明显，巨磁电阻值迅速提高。注入Co离子的颗粒膜的临界增强扩散退火温度约为320℃。更多还原

【Abstract】 In this paper, the granular thin films composed of zero-magnetostriction alloy NiFeCo and non-magnet metal Ag were deposited by DC magnetron sputtering. The effect of ion implantation, annealing and various magnetic concentrations on the films were investigated. The GMR and magnetism of the films were measured by four-point probe device and Vibatinal Sample Magnetometer (VSM) respectively The structure of the films was determined by X-ray Diffiaction (XRD). The component of the films was analyzed by Rutherford Backscattering Spectroscopy (RBS). The surface image, section image and magnetic domain were observed by Field Electron Microscope (FEM), Atom Force Microscope (AFM) and Magnetic Force Microscope (MFM) respectively. The results showed that:The technique characteristic of self-designed and self-manufactured RFMS-4 sputtering apparatus with special magnet field distribution was stable and creditable. The concenlration and deposition rate of the films were stable by the optimal craft on the RFMS-4 sputtering apparatus.For the NIFeC0/Ag granular thin films without ion implantation: the optimal annealing temperature was 30(YC and the optimal magnetic concentration was 36%, and the best GMR was 5% in 300K and 19Gb in 20K(the magnetic field up to 7.6KOe).The best GMR of the film with Fe ion implantation was 2.3% and reach to 90/o after annealing (the magnetic field up to lOKOe in 300K), but the highest GMR of the film with Co ion implantation was 5.5% and reach to 9.8% after annealing. This is the highest value of the granular films made by ion implantation in the world until now.The effect of Co ion implantation was more obvious than Fe ion implantation when it was annealed at lower temperature, but their GMIR were close when annealing at higher temperature.The optimal annealing temperature was changed to 360 ~C and the optimal magnetic concentration was unchanged of the NiFeCo/Ag granular thin films after Fe ion or Co ion implantation. There existed a critical strengthen diffuse annealing temperature in the NiFeCo/Ag granular thin films with ion implantation. Strengthen diffuse effect was very obvious after the annealing temperature reached to the critical temperature, and the GMIR was greatly increased. The critical strengthen diffuse annealing temperature of NiFeCo/Ag granular thin films with Co ion implantation was 320 0C更多还原