Strengthening nanocomposite magnetism through microemulsion synthesis

作     者：Yijun xie Alexandre H. Vincent Haeun Chang Jeffrey D. Rinehart 

作者机构：Materials Science and Engineering Program University of California San Diego 9500 Gilman Drive La Jolla CA 92093 USA Department of Chemistry and Biochemistry University of Cafifomia San Diego 9500 Gilman Drive La Jolla CA 92093 USA 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2018年第11卷第8期

页      面：4133-4141页

核心收录：

学科分类：082604[工学-军事化学与烟火技术] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 0826[工学-兵器科学与技术] 

基　　金：support from the Office of Naval Research Young Investigator Award 

主　　题：nanoparticle cluster microemulsion exchange bias exchange interaction coercivity 

摘      要：The magnetic strength and versatility of heterostructures generated via a simple microemulsion cluster-formation technique is demonstrated. This approach allows optimization of individual component magnetic nanoparticles prior to heterostructuring, expediting the discovery and optimization of hybrid magnetic materials. The efficacy of this method is validated through a magnetic study of nanoparticle clusters combining antiferromagnetic CoO and superparamagnetic CoFe204 nanoparticles with tunable particle ratio and size. An enhancement of coercivity compared with pure CoFe204 nanoparticles indicates that close interparticle contacts are achieved. Upon annealing, an exchange bias field of 0.32 T was observed--over twice that achieved in any other colloidally-synthesized system. Additionally, the unique microstructure is defined during cluster formation and thus protects magnetic coercivity during the annealing process. Overall, this work demonstrates a general approach for quickly exploring magnetic parameter space, designing interparticle functionality, and working towards the construction of high-value bulk magnets with low materials and processing cost.