基于KNN单晶多铁异质结构的制备和电控微波谐振特性研究

The rapid development of microwave communication technology put forward higher requirements for high temperature stability of tunable RF and microwave devices. Ferroelectric/magnetic multiferroic heterostructure, due to the large magnetoelectric coupling effect in areas such as microwave sensing and detection, has good prospects. This project aims to achieve electro-controlled microwave resonance of lead-free Sodium Potassium Niobate (KNN) single crystal based multiferroic heterostructure with high temperature stability. This project will use high-piezoelectric-activity and high-phase-transition-temperature lead-free perovskite ferroelectric single crystals KNN as substrate, through depositing CoFeB magnetic thin films using magnetron and ion beam sputtering method, to obtain multiferroic heterostructures; research on the electromagnetic parameters tunability of the structure at microwave frequencies; through characterizing micro-mechanic and acoustic response of ferroelectric single crystal under applied electric field acoustic response, in-situ controlling micro-structural change of thin film, measuring the ferromagnetic resonance effects of multiferroic heterostructure, and evaluating the temperature stability, to establish the relationship about "strain-microstructure-microwave magnetoelectric coupling property"; combine first principle and phase field simulation methods to analysis the interaction between ferroelectric and magnetic domains, to explore electrical-field controlled microwave resonance mechanism of multiferroic heterostructures; provide theoretical and experimental foundations for the application in the field of modern microwave detection for multiferroic heterostructure based on lead-free ferroelectric single crystal.

微波通信技术的飞速发展对高温度稳定性的可调谐射频微波器件提出了更高的要求，铁电/磁性多铁异质结构，因具有较大磁电耦合效应在微波传感探测等领域有着广阔的应用前景。本项目旨在实现基于铌酸钾钠（KNN）单晶多铁异质结构的高温度稳定性电控微波谐振，拟以高压电性能、高相变温度的无铅铁电单晶KNN为衬底，采用磁控与离子束联合溅射法沉积钴铁硼（CoFeB）磁性薄膜获得多铁异质结构，研究该结构微波频段电磁参数的可调谐性质，通过对外加电场下铁电单晶的微观力学声学响应、原位调控磁性薄膜微结构变化和多铁异质结构铁磁共振效应及其温度稳定性的测试表征，建立“应变－微结构－微波磁电耦合性能”三者之间的相互关系，结合第一性原理和相场模拟方法分析单晶铁电畴与薄膜磁畴间的耦合作用，探索多铁异质结构的高温度稳定性电控微波谐振机理，为无铅铁电单晶多铁异质结构在现代微波探测领域中的应用提供一定的理论和实验基础。

本项目设计了基于Fe、Mn变价元素的几种巨（高）介电（铁电）材料，对其介电性能、介电来源和调控机理进行了探索，以铁电材料为基底搭建氧化物异质结界面，对体系的电子结构和输运特性进行了研究，结合铁电单晶高压电性能、高相变温度和低矫顽场的优点，采用磁控和离子束联合溅射法生长磁性薄膜制备出铁电/磁性多铁异质结构，通过对外加电场下铁电单晶的微观力学声学响应、原位调控磁性薄膜微结构变化和多铁异质结构铁磁共振效应及其温度稳定性的测试分析，建立“应变－微结构－微波磁电耦合性能”三者之间的相互关系，实现多铁异质结构高温度稳定性的电控微波谐振，并对其磁电耦合性能进行了探索。