钴铁氧体纳米管阵列制备及其磁学性能(英文)  

Fabrication and Magnetic Properties of Cobalt Ferrite Nanotube Arrays

作　　者：徐宝龙[1] 孙海燕[2] 都有为[3,4] 

机构地区：[1]烟台大学光电信息科学与技术学院,烟台264005 [2]烟台大学环境与材料工程学院,烟台264005 [3]南京大学固体微结构物理国家重点实验室,南京210093 [4]南京大学物理学院,南京210093

出　　处：《纳米技术与精密工程》2011年第2期95-99,共5页Nanotechnology and Precision Engineering

基　　金：国家自然科学基金资助项目(10704065);山东省自然科学基金资助项目(Y2004A11)

摘　　要：为了研究一维钴铁氧体纳米管阵列的磁学性质,应用氧化铝模板具有的约束作用和毛细管作用,结合溶胶凝胶技术合成了钴铁氧体纳米管阵列.在140℃条件下,通过包含Fe(AO)3和Co(AO)2(物质的量之比为2∶1)的柠檬酸和乙二醇混合溶液(物质的量之比为1∶4)酯化反应得到溶胶.将氧化铝模板浸入溶胶几次后取出,取出充满溶胶的氧化铝模板,在大气气氛中,以0.6℃/min～5℃/min的升温速度将样品由室温升温至500℃,保温8 h.结果表明,在控制Fe3+离子浓度的条件下也可以合成钴铁氧体纳米线(Fe3+离子浓度大于1 mol/L)和"竹节"型纳米管(Fe3+离子浓度介于0.5 mol/L～1.0 mol/L),但重点进行了其纳米管阵列(Fe3+离子浓度小于0.5 mol/L)合成和磁学性能测试.透射电子显微镜(TEM)、高分辨电镜(HRTEM)的观察以及粉末X光衍射(XRD)测试结果表明纳米管组成为多晶结构.纳米管的直径取决于氧化铝模板的孔径,大约为200 nm,其长度约几个微米.应用样品振动磁强计对样品磁性进行了表征,结果表明纳米管阵列未表现出方向特性,矫顽力随着升温速率的降低而升高,在0.6℃/min的升温速率时,矫顽力达到最高的1 445 kOe,简单讨论了其形成原因.On the basis of the confinement effect and capillary force of nano-channel alumina template（NCAT）,magnetic cobalt ferrite nanotube arrays were synthesized in sol-gel process and their magnetic properties were studied.The sol was formed by esterification of the mixture solution of citric acid and ethylene glycol with a molar ratio of 1：4 containing the metal precursor salts Fe（AO） 3 and Co（AO） 2 withthe molar ratio of 2：1 at 140 ℃.NCAT was dipped into the sol several times and taken out,filled with sol,which was annealed at 500 ℃ for 8 h in the open air.The temperature was raised from room temperature to 500 ℃ with the heating rate of 0.6 ℃/min-5.0 ℃/min.The focus of the study was on the fabrication and magnetic properties of cobalt ferrite nanotube arrays（with concentration of Fe3 ＋ less than0.5 mol/L）,although experimental results indicate that cobalt ferrite nanowires（with concentration ofanode ions Fe3 ＋ more than 1 mol/L） and ＂bamboo＂ type nanotube arrays（with concentration of anodeions Fe3 ＋ ranging from 0.5 mol/L to 1.0 mol/L） could be synthesized through control of Fe3 ＋ concentration.Transmission electron microscope（TEM）,high-resolution transmission electron microscope（HR-TEM） images and X-ray diffraction（XRD） pattern show that the nanotubes were in the polycrystal linephase,with the length of several microns and the diameter of about 200 nm,which was dependent on thesize of NCAT.Vibration magnetometer was used to investigate the magnetic properties of the sample of cobalt ferrite nanotube arrays,which indicates that the arrays of nanotube do not show a preferential magnetic orientation,and the coercivity increase with the decrease of heating rate and reach a maximum of1 445 kOe at the heating rate of 0.6 ℃/min,the reasons for which were discussed briefly.

关 键 词：氧化铝模板 溶胶-凝胶法 钴铁氧体 纳米管阵列 磁学性能 

分 类 号：TB383.1[一般工业技术—材料科学与工程]