Characterization Of Magnetoelectric Composite Films And Design Of The Corresponding Filter

Multiferroic magnetoelectric composite materials have attracted great attention for their excellent multiferroicity and magnetoelectric coupling effect,since they were first discovered,and have shown great vitality in modern electrons,reconnaissance and communications,etc..In the meantime,the rise of magnetoelectric composite materials has provided new opportunities for the designing and implementation of modern tunable microwave devices and has become a rising star in functional materials,presenting significant value both in theory and practice.Recently,various performance indexes of magnetoelectric composite materials are improved effectively with the introduction of particular elemental doping and substitution mechanism,thus unveiling a prelude to design and explore new systems of magnetoelectric composite materials.With the development and expansion of thin film technology,magnetoelectric composite films have aroused increasingly the concern of researchers because of their unique glamour,which has made plentiful and substantial achievements both in scientific research and practical applications.Among all of film making techniques,Sol-gel?a liquid-solid phase transfer process?has shown its popularity in contemporary science research for its excellent properties,such as simpler preparation conditions,synthetic films of high quality,easier doping,greater evenness of doping,easier large-scale preparation,and it can synthesize any advanced functional materials under the right conditions,etc..In this text,Pb(Zr_1-xTi_x)O₃,BiFeO₃ and their La³⁺ and Nd³⁺ doped series,together with Ni_1-xZn_xFe₂O₄ films grown on a Pt?111?/Ti/SiO₂/Si?100?substrate were prepared via a sol-gel method and rapid thermal treatment process.After the performance characterization in detail,Bi_0.9Nd_0.1FeO₃?BNF?was selected out as a ferroelectric phase to composite with Ni_0.55Zn_0.45Fe₂O₄?NZF?and as a ferromagnetic phase tocomposite with Pb(Zr_0.52Ti_0.48)O₃?PZT?to form bilayer nanofilms BNF-NZF and PZT-BNF,whose performances were then characterized systematically.Finally,A simple dual symmetric magnetoelectric tunable band-pass filter,the bandwidth of which is about 1.1 GHz,was designed based on the magnetoelectric coupling effect and ferromagnetic resonance theory according to characteristic parameters of materials has reported in literature,and the corresponding lumped-circuit model was established eventually after rigorous theoretical deduction when complicated factors such as device structure and boundary condition are neglected,then the positive regulation of applied field to the ferromagnetic resonance frequency shift together with the influences of applied electric and magnetic fields on scatting parameters were analyzed by ADS quantitatively,providing an innovative new idea for the design of a novel filter.