摘要
以Bi(NO3)3.5H2O、NH4VO3和Mn(CH3COO)2.4H2O为原料,采用溶胶凝胶法在LaNiO3(LNO)/Si(100)衬底上制备了Bi2Mn0.1V0.9O5.35-δ(BIMNVOX.10)薄膜,并通过X射线衍射(XRD)、扫描电镜(SEM)和原子力显微镜(AFM)研究了薄膜的晶体结构和形貌。结果表明,BIMNVOX.10薄膜具有(001)择优取向,晶粒大小均匀,厚度约300 nm。分别用阻抗分析仪和磁测试系统测量薄膜的电学特性和磁特性。BIMN-VOX.10薄膜的I～V曲线表明薄膜漏电流在低场下满足欧姆定律,符合Poole-Frenkel发射机制;而在1.7 V以上的较高场强下符合空间电荷限制传导的Schottky发射机制。低频范围BIMNVOX.10薄膜的介电损耗现象主要来源于氧空位的短程扩散。交流电导符合Jonscher规律,低频范围主要对应几乎与频率无关的直流电导(阱内跃迁);高频范围对应由晶粒响应产生的交流电导(阱间跃迁)。样品主要表现出晶粒电导特性,阻抗谱偏离理想的Debye模型。BIMNVOX.10薄膜中观察到弱铁磁性,5.57×105 A/m(7 kOe)的磁场下剩余磁化强度为8.14×10-7 A/m(1.05×10-4 emu/g),氧空位可能是引起铁磁性的主要原因。
Bi2Mn0.1V0.9O5.35-δ（BIMNVOX.10） thin films were fabricated on LaNiO3（LNO）/Si（100） substrates by sol-gel process,using Bi（NO3）3·5H2O,NH4VO3 and Mn（CH3COO）2·4H2O as raw materials.The crystallite structure and morphology of BIMNVOX.10 films were investigated by X-ray diffraction（XRD）,scanning electron microscope（SEM） and atomic force microscope（AFM）.The results indicated that the films assumed preferred（001） orientation and the film thickness was about 300 nm with a uniform grain distribution.The electrical properties and ferromagnetism were measured by impedance analyzer and physical property measurement system.At a lower electric field,the I-V curves of BIMNVOX.10 films obeyed a Poole-Frenkel emission mechanism,suggesting that the conduction mechanism of leakage current may be attributed to the ohmic conduction.While at a higher electric field above 1.7 V,the current resulted from the combination of Schottky and space charge limited conduction emission mechanism.A low frequency dielectric dispersion was observed in the BIMNVOX.10 thin films.This behavior may be originated from the short distant diffusion of oxygen vacancies.The ac conductivity spectra obeyed Jonscher＇s form.It revealed that the existence of low frequency independent region（dc conductivity） arised from the intra-well hopping domination.Plateau at higher frequencies was referred to the bulk effect associated with ac conductivity（inter-well hopping domination）.The conductive property mainly contributes to the grain resistivity and the impedance spectra for the films differ from the idea Debye model.A weak room temperature ferromagnetism（FM） was observed in the BIMNVOX.10 thin films with remnant magnetization of 8.14×10-7 A/m（1.05×10-4 emu/g） at a magnetic field of 5.57×105 A/m（7 kOe）,in which the oxygen vacancy defects may play a critical role for the FM.
出处
《分析测试学报》
CAS
CSCD
北大核心
2011年第8期868-871,876,共5页
Journal of Instrumental Analysis
基金
国家自然科学基金资助项目(61076060)
华东师范大学优秀博士研究生培养基金资助项目(20080051)
江西省教育厅科技项目(GJJ11181
GJJ08417)
