第3期 田晓霞等:溶胶一凝胶法制备CoFe 0 /TiO 纳米复合薄膜及其磁性能研究 89 理的样品,宏观上晶粒分布均匀、结构致密平整。由于TiO 基体的存在控制了CoFe O 晶粒的大小,对比不 同条件下得到的样品形貌可知,薄膜的生长对反应的热处理温度依赖性较大。 一一一一 (a) (b) (c) (d) 图3不同温度热处理的样品表面形貌SEM图 Fig.3 SEM micrographs of the composite films at diferent heat treatment temperatures ∞舳砷∞加O加∞印舳 图4是CoFe O /TiO:复合薄膜的磁滞回线。6o0℃、7o0℃、8o0℃热处理的样品,其最大磁化强度分别 为50.0 emu/cm 、82.6 emu/cm 、150.0 emu/cm ,比较不同温度热处理后的薄膜的磁滞回线可以看出,在1T 的磁场下,薄膜的最大磁化强度随热处理温度升高而升高,说明随着热处理温度的升高,复合薄膜中磁性粒 子的尺寸逐渐增长 川,薄膜的磁性增强。CoFe O 具有反尖晶石结构,块体钴铁氧体是传统的硬磁材 料 7 J,CoFe O /TiO 复合薄膜与其比较磁性减弱,这一方面是TiO 的存在对CoFe O 有稀释作用;另一方面 钴铁氧体中Co¨随热处理温度不同,既可以位于四面体位置(A位),也可以位于八面体位置(B位),净磁矩 M与Co¨离子占据四面体位置的含量密切相关,Co“离子占据四面体的数量越多,则磁化强度越大¨¨。因 此可以认为,CoFe O /TiO 复合薄膜的磁性和最大磁化强度随热处理温度的变化主要是由于co 离子分布 图4经过不同温度处理后的复合薄膜磁滞回线 Fig.4 Magnetic hysteresis loops of the composite films obtained after heat treatment at cliferent temperature 3结论 1)以钛酸丁酯和三氯化铁、氯化钴制备了前驱体,通过溶胶凝胶工艺可制得磁性CoFe 0 /TiO 纳米复 合薄膜; 2)热处理温度较低,材料以非晶态存在,当热处理温度达到600 ̄C时,TiO 基体中已经有CoFe O 晶体 形成,随热处理温度升高,晶粒逐渐长大。8o0℃可得到表面平整,CoFe O 晶粒平均粒径约为19 nm的纳米 复合薄膜; 3)随着热处理温度的升高,复合薄膜最大磁化强度增大,磁性增强。 参考文献: [1] Gall Le H,Sbiaa R,Pogossian S.Present and Future of Magnetoptical Recording Materials And Technology[J].Alloys Compd,1998,275:677—684. [2] Bursik J,Simsa Z,Stichauer L,et a1.Magneto—optical Properties of Co—and Ti—substituted Hexagonal Ferrite Films Pre. pared By the Sol—gel Method[J].Magn Magn Mater,1996,157:311~312. [3]Laurence B,Philippe T,Abel R,et a1.Relations Between Magneto—optical Properties and Reactivity in Cobalt—manganese Ferrite Thin Films and Powders[J].Magn Magn Mater,1996,153:389—396. 维普资讯 http://www.cqvip.com 空军工程大学学报(自然科学版) 2008拒 [4]干福熹.信息材料[M].天津:天津大学出版社,2000. GAN Fuxi,Information Materials[M].Tianjin:Tianjin University Press。2000.(in Chinese) [5]Ponce Castaneda S,Martinez J R,Ruh F.Synthesis of Fe2 O3 Species Embedded in A Silica Xerogel Matrix:A Comparative Study[J].Sol—gel Sci Teehol,2002,25:29—36. [6] Chinnasamy C N,Jeyadevan B,Shinoda K,et a1.Unusually High Coereivity and Citieal Single—domain Size of Nearly Mono— dispersed CoF%04 Nanopartieles[J].Appl Phys Lett,2003,83:2862—2864. [7]邓联文,江建军.FeCoB—SiO 磁性纳米颗粒膜的微波电磁特性[J].物理学报,2004,53(12):4359-4363. DENG Linawen,JIANG Jianjun.Microwave Electromagnetic Characteristics of FeCoB—SiO2 Nano—granulra Magneitc Films [J].J Aeta Phys Sin,2004,53(12):4359—4363.(in Chinese). [8]黄祥卉,陈振华.纳米CoFe2O /SiO2磁性复合体的制备与表征[J].科学通报,2006,6,(51):660—664. HUANG Xinaghui。CHEN Zhenhua.Preparation and Characterization of CoFe204/SiOz Nanoeomposites[J].J Chin Sei Bull, 2006,20(51):660—664.(in Chinese) [9]Dinaa Mardam,Alexandru Stnaeu. On the Optical Constnats of TiO2 n Films,Ellipsometrie Studies[J]. Materilas Research Bulletin,2000,35:2017—2025. [10]陈祖熊,王坚.精细陶瓷——理论与实践[M].北京:化学工业出版社,2005. CHEN Zuxiong,WANG Jian.Fine Ceramic—heoreties and Practice[M].Beijing:Chemistry Industry Press,2005.(in Chi- nese) [11]汪金芝,方庆清.纳米ZnO.6CoxFe2 一xO 晶粒的结构相变与磁性研究[J],物理学报,2004,53(9):3186—3190. WANG Jinzhi,FANG Qingqing.Structure Phase Transition nad Magnetic rPoperties of Nanoerystlaline ZnO.6CoxFe2.4一xO4 [J].J Chin Phys Soc,2004,53(9):3186—3190.(in Chinese) [12]Ponce Castnaeda S,Martinez J R,Ruiz F.Synthesis of Fe2 O3 Species Embedded in A Sihea Xerogel Matrix:A Comparative Study[J].Sol—gel Sci Teehol,2002,25:29—36. [13]王保国,王素梅,张金利,等.纳米晶TiO 半导体薄膜的制备和性能[J].化学工业与工程,2005,22(1):1—4. WANG Baoguo。WANG Sumei,ZHANG Jinli,et a1.Preparation and Characterization of Nano—crystalline TiO2 Sensing Film [J].J Chemical Lndustyr nad Engineering,2005,22(1):1—4.(in Chinese) (编辑:田新华,徐楠楠) Preparation of CoFe2 O4/TiO2 Nano—composites Thin films by Sol——Gel Method and Study of Magnetic Properties TIAN Xiao—xia,PEI Zhi—bin,QU Shao—bo,WANG Bin—ke (Science Institute,Air Force Engineering University,Xi an 710051,China) Abstract:CoFe2 O4/TiO2 nano—composite iflms were prepared using the sol—gel method wiht tetrabutyltitanate and metallic chlorates as starting materials.The phase structure and microstructure properties of the samples were stud— ied by X—ray difractometer,Raman spectrum,scanning electron microscopy.The magnetic properties of the com— posite films were characterized by vibrating sample magnetometry.The results show that crystals of different sub— stances grow up independently without producing new phases,and the growth of composite films is dependent on the heat treatment temperature.The grain size of Cobalt ferrite is controlled by the titanium dioxide matrix in the pre— pared composite films,the average size of CoFe2 O4/TiO2 is 19nm in nano—composite film prepared at 800 ̄C and pH=2—3 of hte precursor.The magnetism of the composite films is enhanced wiht an increase of the heat treat— ment temperature. Key words:CoFe2 O4/TiO2;nano—composite fimls;magnetism;sol—gel
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