基于化学诱导相变法的磁性液体合成及其磁光效应  

Synthesis of Ferrofluids Based on Chemically Induced Transition and Their Magneto-Optical Effects

作　　者：刘林[1] 孟祥申[2] 林跃强[2] 李建[2] LIU Lin;MENG Xiang-shen;LIN Yue-qiang;LI Jian(School of Electronic and Information Engineering,Southwest University,Chongqing 400715,China;School of Physical Science and Technology,Southwest University,Chongqing 400715,China)

机构地区：[1]西南大学电子信息工程学院,重庆400715 [2]西南大学物理科学与技术学院,重庆400715

出　　处：《西南大学学报（自然科学版）》2018年第7期73-78,共6页Journal of Southwest University(Natural Science Edition)

基　　金：国家自然科学基金项目(11074205)

摘　　要：使用化学诱导相变法制备的γ-Fe_2O_3磁性纳米颗粒,经油酸表面包裹可分散于煤油中合成磁性液体.在磁场作用下,圆偏振光透过磁性液体样品后,由于双折射效应和二向色性,透射光为椭圆偏振光.用圆偏振光作为探测光源,使用θ扫描技术可得到透射椭圆偏振光的相对强度角分布的T-θ曲线.从曲线可得到反映透射椭圆偏振光特征的相对透射强度的最小值T_(min)和最大值T_(max)以及椭圆的取向角Δθ.从这些透射光的参数可导出磁双折射效应Δn和磁二向色性Δκ.实验结果表明:随着磁场H增强或颗粒体积分数v增大,Δn和Δκ增加.所制备的磁性液体的磁双折射和磁二向色性来源于在磁场作用下,磁性液体中的磁性纳米颗粒由分散体系形成了场致链结构.Magnetic nanoparticles ofγ-Fe2O3 prepared with the method of chemically induced transition and wrapped in a layer of membrane-like surface with oleic acid can be dispersed in kerosene to synthesize ferrofluids.When a circularly polarized light travels through a ferrofluid sample in the presence of an external magnetic field,magnetic birefringence and magnetic dichroism effects cause the transmitted light to behave as an elliptically polarized light.Using circularly polarized light as the illumination source and theθ-scan technique,aT-θcurve with the angular distribution of relative intensity for the transmitted light,which corresponds to elliptically polarized light,is obtained.From the T-θcurve,the T（min）,T（max）of relative transmission strength and the orientation angle（OA）of the ellipseΔθcan be obtained.According to these parameters,information of the magnetic birefringenceΔn and the dichroismΔκcan be deduced.Experimental results indicate that bothΔn andΔκincrease with the applied magnetic field strength or the particle＇s volume fraction in the ferrofluids.For the ferrofluids,the magnetic-optical effects result from the formation of a chain-like structure from the dispersed particle system under the external magnetic field.

关 键 词：磁性液体 合成 磁光效应 圆偏振光 θ扫描技术 

分 类 号：O482.54[一般工业技术—材料科学与工程] TM27[理学—固体物理]