Cr^(3+)掺杂对Mn_(3)O_(4)结构、形貌以及磁电性能的影响  

Effects of Cr^(3+)doping on the structure,morphology,magnetic and dielectric properties of Mn_(3)O_(4)

作　　者：崔梦范 王松伟[1,2] 张鑫[1,2] 杨瑞鑫 张亚乐 邓胜龙 周欣 CUI Mengfan;WANG Songwei;ZHANG Xin;YANG Ruixin;ZHANG Yale;DENG Shenglong;ZHOU Xin(School of Materials Science and Engineering,Guilin University of Electronic Technology,Guilin 541004,China;Guangxi Key Laboratory of Structure-Activity Relationship for Electronic Information Materials,Guilin University of Electronic Technology,Guilin 541004,China)

机构地区：[1]桂林电子科技大学材料科学与工程学院,广西桂林541004 [2]桂林电子科技大学广西电子信息材料构效关系重点实验室,广西桂林541004

出　　处：《桂林电子科技大学学报》2024年第3期292-298,共7页Journal of Guilin University of Electronic Technology

基　　金：国家自然科学基金(51802052);广西信息材料重点实验室基金(191004-Z,201021-Z,201020-Z,211014-Z)。

摘　　要：为了探究Cr^(3+)掺杂对Mn_(3)O_(4)体系磁电效应的影响,采用传统固相法成功制备了Mn_(3)O_(4)及Mn_(1.8)Cr_(1.2)O_(4)的单相多晶样品。X射线衍射及精修结果表明,掺杂前后存在晶体结构的改变,由四方晶系转变为立方晶系,其空间群由I41/amd变为Fd3m。场发射扫描电镜结果显示,掺杂前样品的晶粒呈紧密的镶嵌结构,掺杂后样品呈离散的五面体及八面体形貌,且尺寸约是掺杂前的1/8。磁性研究结果表明,掺杂前、后样品Yafet-Kittel型亚铁磁相变温度由43 K提高到60 K,这源自Cr^(3+)掺杂使Mn^(3+)(Cr^(3+))/Mn^(2+)—O键长缩短,Mn^(3+)(Cr^(3+))—O—Mn^(3+)(Cr^(3+))键角增大,磁相互作用增强。此外,掺杂后矫顽力显著降低,这可根据离散的晶粒间作用力减小来理解。介电效应研究发现,掺杂前、后样品在磁相变点附近存在不随频率移动的介电异常峰,表明该体系存在与磁序相关的铁电极化,这源自体系的非线性磁结构。Mn_(3)O_(4)and Mn_(1.8)Cr_(1.2)O_(4)single-phase polycrystalline samples were successfully prepared by the conventional solid-phase method in order to investigate the effect of Cr^(3+)doping on the magnetoelectric effect of the Mn_(3)O_(4)system.The results from Rietveld refinement of powder X-ray diffraction patterns show a change in crystal structure after Cr^(3+)doped Mn_(3)O_(4),from a tetragonal(space group I41/amdI41/amd)to a cubic(space group Fd3m)crystal system.Field emission scanning electron microscopy results indicate that the morphology of Mn_(3)O_(4)is with a tight mosaic structure,while Mn_(1.8)Cr_(1.2)O_(4) manifests as discrete pentahedronlike and octahedron-like.Moreover,the grain size of Mn_(1.8)Cr_(1.2)O_(4) is about 1/8 times of that of the Mn_(3)O_(4).Magnetization measurements show that the Yafet-Kittel type ferrimagnetic phase transition temperature increases from 43 K to 60 K after Cr^(3+)doping,which is due to the enhancement of the magnetic interaction from the decrease of the Mn^(3+)(Cr^(3+))/Mn^(2+)-O bond length and the increase of the Mn^(3+)(Cr^(3+))-O-Mn^(3+)(Cr^(3+))bond angle.In addition,the coercivity of Mn_(1.8)Cr_(1.2)O_(4) decreases significantly,which can be understood in terms of the reduction in force between crystalline grains.The dielectric effect study shows that the dielectric anomaly peaks are observed in Mn_(3)O_(4)and Mn_(1.8)Cr_(1.2)O_(4) near the magnetic phase transition temperature,and the dielectric anomaly peak positions don't shift with frequency,indicating that the systems exist ferroelectric polarization related to the magnetic order,which originates from the nonlinear magnetic structure of the system.

关 键 词：固相法 Cr^(3+)掺杂 磁性测量 介电测量 磁电耦合 

分 类 号：TQ581[化学工程—精细化工]