NiCo_(2)O_(4)薄膜的制备及其磁电性能研究  

Preparation and Magnetoelectric Properties of NiCo_(2)O_(4) Thin Films

作　　者：周国伟[1] 康鹏华 Zhou Guowei;Kang Penghua(Key Laboratory of Magnetic Molecules and Magnetic Information Materia of Ministry of Education,School of Chem-istry and Materials Science,Shanxi Normal University,Linfen 041004,China)

机构地区：[1]山西师范大学化学与材料科学学院,磁性分子与磁信息材料教育部重点实验室,山西临汾041004

出　　处：《稀有金属》2022年第7期975-981,共7页Chinese Journal of Rare Metals

基　　金：国家自然科学基金青年基金项目(51901118)资助。

摘　　要：采用脉冲激光沉积(PLD)技术,在氧化镁(MgO(001))、钛酸锶(SrTiO_(3)(001))和铝酸镁(MgAl_(2)O_(4)(001))3种衬底上,外延生长钴酸镍(NiCo_(2)O_(4))薄膜。采用原子力显微镜(AFM)和X射线衍射仪(XRD)对NiCo_(2)O_(4)薄膜进行形貌表征和结构分析,测试结果表明NiCo_(2)O_(4)薄膜具有平整的表面和优异的结晶度。采用综合物性测量系统(PPMS)测试NiCo_(2)O_(4)薄膜的电输运及磁性能,通过对比发现在MgO(001)和SrTiO_(3)(001)衬底上生长的NiCo_(2)O_(4)薄膜呈半导体特性,并且磁性较弱,而在MgAl_(2)O_(4)(001)衬底上生长的NiCo_(2)O_(4)薄膜具有金属性和室温亚铁磁性,并且表现出明显的垂直磁各向异性。综合分析表明,不同衬底上制备的NiCo_(2)O_(4)薄膜受外延应变、沉积温度(T_(g))及氧分压(p_(O2))的影响,会表现出差异较大的磁电特性。通过优化衬底的选择以及生长参数的调整,本文可以制备出具有垂直磁各向异性的室温亚铁磁金属NiCo_(2)O_(4)薄膜,可用于微型自旋电子学器件的制备。The epitaxial NiCo_(2)O_(4)thin films were grown on MgO(001),SrTiO_(3)(001)and MgAl_(2)O_(4)(001)substrates at different oxygen pressures and temperatures by pulsed laser deposition system(PLD).The lattice constants of MgO,SrTiO_(3),MgAl_(2)O_(4) and NiCo_(2)O_(4)were 0.8432,0.781,0.8083 and 0.8114 nm,respectively.The lattice mismatch between the NiCo_(2)O_(4)films and the different substrates were 3.9%,3.7%and 0.38%,respectively.The surface morphology and the structural characterize of NiCo_(2)O_(4)thin films were charac⁃terized by atomic force microscope(AFM)and X-ray diffraction(XRD).AFM results suggested that the NiCo_(2)O_(4)films growth on MgO and SrTiO_(3) substrates presented some particles on the surface and larger roughness.When NiCo_(2)O_(4)films grew on MgAl_(2)O_(4) substrate,the films surfaces were smooth and the roughness was smaller.The reason for the greater roughness of NiCo_(2)O_(4)films growth on high oxy⁃gen pressures was attributed to the oxygen diffusion in the films during deposition process which would lead to an increase in the oxy⁃gen content in the NiCo_(2)O_(4)films,resulting in the formation of some particles on the film surface.XRD results showed that the highquality crystal structures existed in these NCO thin films.The 2θpeak positions of NiCo_(2)O_(4)films grown on MgO,SrTiO_(3) and MgAl_(2)O_(4) substrates were at 44.9°,43.9°and 44.4°,respectively.The shift in the peaks of NiCo_(2)O_(4)films grown on different substrates was due to a large lattice mismatch between the different substrates and NiCo_(2)O_(4)films.The magnetic and electrical properties of NiCo_(2)O_(4)films were measured by physical property measurement system(PPMS)combined with external resistivity and vibrating sample magnetome⁃ter(VSM)option.According to the resistance dependence on temperature test results,the resistance of NiCo_(2)O_(4)films growth on the MgO substrate increased slowly with the decrease of temperature.And with the increase of oxygen pressure,the resistance of NiCo_(2)O_(4)films pre

关 键 词：脉冲激光沉积 NiCo_(2)O_(4)薄膜 金属性 室温亚铁磁 垂直磁各向异性 

分 类 号：O484.1[理学—固体物理]