Synthesis and Characterization of Bi2Mn0.1V0.9O5.35-¦Ä Thin Films

KeyWord:Bi2Mn0.1V0.9O5.35-¦Ä£¨BIMNVOX.10£©  electrical conductivity  ferromagnetism  oxygen vacancies

Abstract:

      Bi2Mn0.1V0.9O5.35-¦Ä£¨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¡Á10-7 A/m£¨1.05¡Á10-4 emu/g£© at a magnetic field of 5.57¡Á105 A/m£¨7 kOe£©,in which the oxygen vacancy defects may play a critical role for the FM.