Magnetic dielectric and magnetoelectric properties of CoFe2O4 and K0 5Na0 5NbO3 composite

  • 葉 治均

Student thesis: Doctoral Thesis

Abstract

Magnetoelectric composites of CoFe2O4 (CFO) and K0 5Na0 5NbO3 (KNN) were synthesized by solid-state sintering method The composition and microstructure of obtained samples were examined by X ray diffraction and scanning electron microscopy The results showed a uniform mixture of both components in the composites without presence of any secondary phase Dielectric constant and loss of the samples were studied by the impedance analysis The piezoelectricity of the samples was confirmed by the measurement of d33 coefficient Magnetoelectric (ME) voltage coefficient was investigated by a home-made unit which allowed simultaneously application of both an AC (50 Hz~100 kHz) magnetic field of about 6 Oe and a DC bias field up to 6000 Oe Under zero DC bias the highest ME coefficient was measured at 2 5 kHz with the 80-20 vol% CFO-KNN samples which was 0 62 mV/Oe?cm With the application of a DC bias of 2 7 kOe the highest ME coefficient was increased to 3 63 mV/Oe?cm at the AC frequency of 2 5 kHz which was achieved with the 50-50 vol% CFO-KNN samples
Date of Award2020
Original languageEnglish
SupervisorXiao-Ding Qi (Supervisor)

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