Co-C颗粒膜的结构、磁性能和GMR效应研究  

Structure, Magnetic Property and GMR Effects of Co-C Granular Thin Films

作　　者：马垒[1,2] 刘仲武[2] 曾德长[2] 钟夏平[2] 成钢[1] 

机构地区：[1]桂林电子科技大学广西信息材料重点实验室,广西桂林541004 [2]华南理工大学材料科学与工程学院,广东广州510640

出　　处：《稀有金属材料与工程》2013年第8期1659-1663,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(U0734001);广西自然科学基金(2012GXNSFGA060002;2013GXNSFBA019242);中央高校基础研究基金(2012ZZ0015);广西信息材料重点实验室项目(1110908-04-Z)

摘　　要：采用直流磁控溅射技术,在n-Si(100)衬底上制备了Cox C100-x(x=2.5～50,at%)颗粒膜,并对薄膜的结构、形貌、磁性能和巨磁电阻(GMR)效应做了系统的研究。结果表明:制备态的Co-C薄膜为非晶结构,且表面光滑、颗粒尺寸及膜厚度均匀;随热处理温度的增加,Co成分在300℃逐渐开始晶化,400℃基本晶化完全,500℃度的时候膜层开始出现裂纹;拉曼光谱显示制备态薄膜为类金刚石(DLC)薄膜;X射线光电子能谱(XPS)分析表明,包埋在碳基薄膜中的Co掺杂纳米颗粒以单质形态存在,没有Co的碳化物出现,且Co掺杂没有促进碳膜的石墨化,Co-C纳米复合薄膜组成了一个互不相溶的金属/绝缘体体系;磁性能测试显示薄膜的饱和磁化强度(Ms)和矫顽力(Hc)与Co的含量和颗粒的晶化程度有密切关系;磁电阻测量结果表明Co2.5C97.5薄膜具有高达36%的正GMR效应,GMR效应遵循输运通道的转变机制。CoxCl00-x （x=2.5-50, at%） granular films were prepared on n-Si （100） substrates by d.c. magnetron sputtering, and the structure, morphology, magnetic properties and giant magnetoresistive （GMR） effects of the films were investigated. The as-deposited Co-C granular films are amorphous, which have fairly smooth and flat surface. With the increase of annealing temperature, the Co （002） peak of the Co-C films is obtained at 300 ℃, but cracks appear in the films after annealing at 50℃ for 0.5 h. The X-ray photoelectron spectroscopy （XPS） and Raman spectroscopy results show that the as-deposited Co-C films are diamond like carbon （DLC） films, and the doping of Co existing in atomic state does not enhance the graphitization of carbon film. The nano-sized amorphous Co particles are homogeneously encapsulated in the amorphous cross-linked carbon matrix, thereby forming a good metal/insulator system. Saturation magnetization （Ms） and the coercivity （He） of CoxC100-x films are dependent on Co concentration and the amount of crystallized Co. The as-deposited Co2.5C97.5 granular films exhibit a novel positive GMR effect, up to 36%. The GMR effects of the Co-C granular films follow a variable transport channel mechanism.

关 键 词：颗粒膜 DLC膜 GMR效应 磁控溅射 

分 类 号：O484.1[理学—固体物理]