Low-field-induced spin-glass behavior and controllable anisotropy in nanoparticle assemblies at a liquid-air interface  

低场诱导液-气界面纳米颗粒组装体自旋玻璃行为和可控各向异性

作　　者：Xiaoqi Liao Seda Ulusoy Rui Huang Erik Wetterskog Klas Gunnarsson Yu Wang Huawei Liang Yu-Jia Zeng German Salazar-Alvarez Peter Svedlindh 廖晓奇;Seda Ulusoy;黄锐;Erik Wetterskog;Klas Gunnarsson;王宇;梁华伟;曾昱嘉;German Salazar-Alvarez;Peter Svedlindh(College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,China;School of Materials Science and Engineering,Hanshan Normal University,Chaozhou 521041,China;Solid State Physics,Department of Materials Science and Engineering,Angstrom Laboratory,Uppsala University,Box 35,75103 Uppsala,Sweden;MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,China [2]School of Materials Science and Engineering,Hanshan Normal University,Chaozhou 521041,China [3]Solid State Physics,Department of Materials Science and Engineering,Angstrom Laboratory,Uppsala University,Box 35,75103 Uppsala,Sweden [4]MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China

出　　处：《Science China Materials》2022年第1期193-200,共8页中国科学（材料科学（英文版）

基　　金：financially supported by Shenzhen Science and Technology Project(CYJ20180507182246321 and JCYJ20200109105825504);Swedish Research Council VR(2016-06959);financial support from the Doctoral Joint-Training Program of China Scholarship Council.

摘　　要：Stacking nanoscale-building blocks into onedimensional(1D)assemblies with collective physical properties is a frontier in designing materials.However,the formation of 1D arrays using weak magnetic fields and an in-depth understanding of their magnetic properties remain challenging.Here,low-dimensional assemblies of iron oxide nanocubes with a disordered arrangement are fabricated at the diethylene-glycol/air interface in the presence of assembly fields(0/1/3/5/30/50 mT).Ring-shaped assemblies gradually transform as the assembly field increases from 0 to 50 mT,first to a porous network consisting of elongated assemblies and then to an aligned array of filaments,in which the aligned filaments are formed when the assembly field is≥3 mT and duration t>14 min.Spin-glass characteristics and static(dynamic)anisotropy factors~2(3)are achieved by tuning the strength of the assembly field.In the presence of a relatively weak assembly field,the interplay between dipolar interactions and disorder with respect to magnetic easy axis alignment leads to spin-glass characteristics.The alignment of the magnetic easy axes and the strength of the dipolar interactions increase with increasing assembly field,resulting in the disappearance of spin-glass characteristics and enhancement of the magnetic anisotropy.This study presents a strategy for obtaining magnetic assemblies with spin-glass behavior and controllable anisotropy while shedding light on the magnetic interactions of low-dimensional assemblies.利用纳米尺度结构单元堆积成具有丰富物理性能的一维(1D)组装体,是材料设计的研究前沿.然而,弱磁场诱导1D阵列的制备及其磁性能机制的揭示仍然具有挑战性.本文采用强度不同的组装场(0/1/3/5/30/50 mT),在二甘醇-空气界面上制备了由无序四氧化三铁纳米立方体组成的低维组装体.随着组装场从0增长到50 mT,环形组装体先变为细长多孔网状,再逐步变为细丝阵列,其中细丝阵列的合成条件为组装场≥3 mT且施加组装场时间t>14 min.通过调控组装场强度可得到自旋玻璃特性和静(动)各向异性~2(3).在弱组装场下磁偶极和无序排列易磁化轴之间相互作用导致自旋玻璃特性,进一步增大组装场将加强磁偶极作用和易磁化轴排列,导致自旋玻璃特性消失和强各向异性.本研究不仅提出了一种制备自旋玻璃和可控各向异性组装体的策略,还为理解低维组装磁相互作用提供了新思路.

关 键 词：magnetic nanoparticles ASSEMBLY ANISOTROPY spin glass 

分 类 号：TB383.1[一般工业技术—材料科学与工程]