多铁性材料同时具有多种铁性(铁电性、铁磁性或铁弹性)的有序,可实现电磁信号的相互控制,成为近年来研究热点。在具有成分无序的复杂体系中,长程铁性有序有可能被打破,材料将表现出弛豫特性。我们将至少存在一种铁性弛豫特性的多铁性材...多铁性材料同时具有多种铁性(铁电性、铁磁性或铁弹性)的有序,可实现电磁信号的相互控制,成为近年来研究热点。在具有成分无序的复杂体系中,长程铁性有序有可能被打破,材料将表现出弛豫特性。我们将至少存在一种铁性弛豫特性的多铁性材料称之为弛豫多铁性材料。这类多铁性材料的极化强度(或磁化强度)在外加电场(或外加磁场)作用下响应更加灵敏,其磁电耦合机制与长程有序的多铁性材料不同。本文结合国内外最新研究成果,首先介绍了和弛豫铁性有序相关的物理概念,重点阐述了多铁性材料在铁电和铁磁双弛豫态下的磁电耦合机制;然后,详细介绍了钙钛矿结构(包括Pb B_1B_2O_3基和Bi Fe O_3基材料)和非钙钛矿结构(包括层状Bi结构和非正常铁电体)弛豫多铁性材料的研究进展;最后,对该领域亟待解决的问题进行了展望。展开更多
Two compounds Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 with tungsten bronze structure were synthesized in the BaO-ZnO-Nb 2 O 5 /Ta 2 O 5 systems by the conventional high temperature solid-state reaction....Two compounds Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 with tungsten bronze structure were synthesized in the BaO-ZnO-Nb 2 O 5 /Ta 2 O 5 systems by the conventional high temperature solid-state reaction.The stru cture and dielectric properties of Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 were determined by X-ray powder diffraction,scanning electron microscope a nd dielectric measurements.The results show that Ba 6 Zn 0.67 Ta 9.33 O 30 belongs to paraelectric phase of fully filled tetragonal tungsten bronze str ucture at room temperature with unit cell parameters a=1.26256(4)nm, c=0.39698(2)nm.The room temperature dielectric constant( ε )of Ba 6 Zn 0.67 Ta 9.33 O 30 ceramic reached108combined with a low dielectric loss of0.005at1MHz .While Ba 6 Zn 0.67 Nb 9.33 O 3 belongs to fully filled tetragonal tungsten bronze structure at room tempera ture with the unit cell parameters a=1.25940(3)nm,c=0.40008 (2)nm.Ba 6 Zn 0.67 Nb 9.33 O 30 ceramic shows significant relaxor behaviors,and the phase transition from f erroelectric to paraelectric occurred at55℃(at1MHz).The room temperature dielectric constant( ε )of ceramic reached570at1MHz.展开更多
文摘多铁性材料同时具有多种铁性(铁电性、铁磁性或铁弹性)的有序,可实现电磁信号的相互控制,成为近年来研究热点。在具有成分无序的复杂体系中,长程铁性有序有可能被打破,材料将表现出弛豫特性。我们将至少存在一种铁性弛豫特性的多铁性材料称之为弛豫多铁性材料。这类多铁性材料的极化强度(或磁化强度)在外加电场(或外加磁场)作用下响应更加灵敏,其磁电耦合机制与长程有序的多铁性材料不同。本文结合国内外最新研究成果,首先介绍了和弛豫铁性有序相关的物理概念,重点阐述了多铁性材料在铁电和铁磁双弛豫态下的磁电耦合机制;然后,详细介绍了钙钛矿结构(包括Pb B_1B_2O_3基和Bi Fe O_3基材料)和非钙钛矿结构(包括层状Bi结构和非正常铁电体)弛豫多铁性材料的研究进展;最后,对该领域亟待解决的问题进行了展望。
文摘Two compounds Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 with tungsten bronze structure were synthesized in the BaO-ZnO-Nb 2 O 5 /Ta 2 O 5 systems by the conventional high temperature solid-state reaction.The stru cture and dielectric properties of Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 were determined by X-ray powder diffraction,scanning electron microscope a nd dielectric measurements.The results show that Ba 6 Zn 0.67 Ta 9.33 O 30 belongs to paraelectric phase of fully filled tetragonal tungsten bronze str ucture at room temperature with unit cell parameters a=1.26256(4)nm, c=0.39698(2)nm.The room temperature dielectric constant( ε )of Ba 6 Zn 0.67 Ta 9.33 O 30 ceramic reached108combined with a low dielectric loss of0.005at1MHz .While Ba 6 Zn 0.67 Nb 9.33 O 3 belongs to fully filled tetragonal tungsten bronze structure at room tempera ture with the unit cell parameters a=1.25940(3)nm,c=0.40008 (2)nm.Ba 6 Zn 0.67 Nb 9.33 O 30 ceramic shows significant relaxor behaviors,and the phase transition from f erroelectric to paraelectric occurred at55℃(at1MHz).The room temperature dielectric constant( ε )of ceramic reached570at1MHz.
