利用高压手段调控铁电材料结构与性能的研究进展

Research Progress in High Pressure on Tuning the Structural and Physical Properties of Ferroelectric Materials

铁电材料是在一定温度范围内可自发极化的一类重要的功能材料,其自发极化能够通过外加电场进行逆转,在光电调节器和储存器等电子器件中有着极大的应用潜力。目前,由于铁电材料电阻高、载流子浓度低等特点,其应用发展被严重制约。因此,亟需找到一种简单有效的方法来优化铁电材料的铁电性能及其他物理性能。调控压力是调控晶体结构、电子构型和调节材料物理性能的有效手段。较低的压力会影响铁电体内部长程库仑引力和短程电子斥力之间的平衡,导致短程斥力明显增加,铁电性降低。而一旦达到较高的临界压力,材料铁电性就开始增大,并发生铁电相变,其物理性能也会因此发生改变。近年来,国内外对压力调控铁电材料结构和物理性能的研究主要集中在使用压力探究铁电相变及其引起的材料其他物理性能的改变上,并探究其内在影响机制。压力作为调节铁电晶体结构和性能的一个重要因素,可以在一定程度上替代掺杂调控晶体的铁电相变,且相变温度受压力的影响非常小,压力引起的畴壁变化和去老化过程可以改善材料介电和铁电性质,实现其在器件设备中的良好应用;压力可以通过影响弛豫铁电体中的极性纳米畴调节铁电材料的弛豫行为,同时能够改变磁电耦合材料的磁序或对称性,从而改变其铁电性质;在铁电光伏材料的高压相中还可以实现相对于低压相的铁电性、电输运性质和光电性质的同步增强,且利用高压手段还可以进一步探究铁电光伏机理。本文综合国内外铁电材料的高压研究进展,论述了铁电材料在高压条件下的结构演变规律及其发生机制,介绍了高压条件对铁电材料铁电性能、介电性能、弛豫行为、磁电耦合及光伏性能的影响,为利用高压技术研究设计新型高性能铁电材料提供了新思路。

Ferroelectric materials are an important class of functional materials with spontaneous polarization in a certain temperature range.Their spontaneous polarization can be reversed by an external electric field,and they have a wide application potential in electronic devices such as photovoltaic regulators and storage.At present,the development of ferroelectric materials for applications is severely constrained by their high resistance and low carrier concentration,so there is an urgent need to find a simple and effective method to optimize the ferroelectric properties and other physical properties of ferroelectric materials.Pressure control is an effective means to modulate the crystal structure and electronic configuration and regulate the physical properties of materials.Lower pressure can affect the balance between long⁃range Coulomb attraction and short⁃range electron repulsion in ferroelectrics,resulting in an obvious increase in short⁃range repulsion and a decrease in ferroelectricity.However,once the critical pressure is reached,the ferroelectricity begins to increase,and the ferroelectric phase transition occurs,thus changing the physical properties of materials.In recent years,the research on the structure and physical properties of ferroelectric materials regulated by pressure at home and abroad mainly focuses on exploring ferroelectric phase transition and other physical properties of materials caused by pressure,and exploring its internal influence mechanism.As an important dimension to adjust and control the structure of ferroelectric crystals,pressure can replace doping to study the ferroelectric phase transition to some extent,and it can also stabilize the phase transition temperature.The improvement of dielectric and ferroelectric properties of materials due to domain wall change and de⁃aging process caused by high pressure can make the materials well applied in device equipment.Pressure can modulate the relaxation behavior of ferroelectric materials by affecting the polar nano⁃domains,and it can also change the magnetic sequence or symmetry of the magnetoelectric coupling material to change its ferroelectric properties.The synchronous enhancement of ferroelectric,electric transport and photoelectric properties can be realized in the high pressure phase of ferroelectric photovoltaic materials,relative to those in the low pressure phase,and the mechanism of ferroelectric photovoltaic can be further explored by means of high pressure.This review summarizes the high pressure research progress of ferroelectric materials at home and abroad,discusses the structural evolution of ferroelectric materials under high pressure and its occurrence mechanism,and the influence of high pressure conditions on ferroelectric properties,dielectric properties,relaxation behavior,magnetoelectric coupling and photovoltaic properties of ferroelectric materials is introduced.These provide new ideas for the research and design of new high⁃performance ferroelectric materials using high pressure technology.