Preparation And Characterizations Of Co_1+xFe_2-xO₄ Magnetoelectric Thin Film

The magnetoelectric films show great application potentials in the fields of new high-density electro-write magnetic reading devices,low-energy-consumption logic circuits,and spin electronic devices due to the mutual regulation between polarization and magnetic polarization.In this work,we attempts to find a breakthrough in the simpler spinel structure.Based on the spinel structure Co_1+xFe_2-xO4,the composite structure of spinel film and lead-free piezoelectric films is studied and the magnetoelectric coupling properties are studied.A large magnetoelectric coupling effect is realized at room temperature through A-B sites co-doping for Co₂Fe O₄thin films.The specific research contents are as follows:For the research of composite thin films based on the cobalt ferrite,[0.5Ba(Ti_0.8Zr_0.2)O₃–0.5(Ba_0.7Ca_0.3)Ti O₃]–CoFe₂O₄（BZT–0.5BCT/CFO）composite structure thin films have been fabricated,in-situ observation of electric field induced magnetism modulation has obtained for BZT–0.5BCT/CFO composite thin film using a magnetic force microscope.The domain structure varies with the application of electric field,when the voltage is 3V,the area of the magnetic domain changing region of the composite film reaches 49.2%.In the magnetic field excited charge test,at the test frequency of 1 Hz,the maximum polarization of about 0.3μC/cm³is obtained for the sample induced by a magnetic field of 50Oe.Based on Co₂Fe O₄thin film,the field-induced magnetoelectric coupling effect induced by Mg and Al co-doping was studied.The new single-phase spinel structure magnetoelectric thin film was prepared,we analyze the crystal structure,ion valence and ion occupation of Mg-Al co-doped Co₂Fe O₄thin film system by Raman spectroscopy,synchrotron radiation,XPS,combining with piezoelectric hysteresis measurement and CAFM test analysis methods,the mechanism of the magnetoelectric effect in Mg-Al co-doped Co₂Fe O₄thin film was interpreted.