During the last fifteen years, multiferroic (MF) research communities have been searching for an alternative room temperature MF material with large magnetoelectric (ME) coupling for possible applications in high density electronic components, low heat dissipation memory and logic devices. We have studied Pb(Zr0.20Ti0.80)0.70Pd0.30O3-δ (PZTP30) system with an unusually large (30%) palladium occupancy in B site of PZT. This material exhibited a giant ME coupling coefficient ~0.36 mV/cm.Oe. Interestingly, this is the first time any room temperature single phase compound that showed ME trends, and magnitude similar to those in the well established mechanical strain-mediated ferroelectric and ferromagnetic composites; the latter ones are already in the commercial stage as nT/pT magnetic field sensors due to their large ME values. The presence of Pd in PZTP30 has been confirmed by XPS and XRF studies and assigned with related binding energies of Pd+2 and Pd+4 ions as 336.37 eV, 342.9 eV, and 337.53 eV, 343.43 eV, respectively, which may be the origin of room temperature magnetism in Pd substituted PZT ceramics. A sharp first order ferroelectric phase transition was observed at ~569 K (+/-5 K) that is confirmed from dielectric, Raman, and thermal analysis. Both ferromagnetic and ferroelectric orderings with large ME coupling were found above room temperature, a significant step forward in the development of single phase ME material with enhanced functionalities.
University of Jinan(济南大学);Institute for Superconducting and Electronic Materials, Faculty of Engineering and Information Sciences, University of Wollongong(伍伦贡大学工程与信息科学学院超导与电子材料研究所)
Magnetic-Field-Dependent Raman Scattering in Multiferroic Bilayer Films: Evidence for Stress-Mediated Magnetoelectric Coupling
首次报道了Pb(Zr,Ti)O_3-CoFe_2 O_4双层多铁体系的磁场相关拉曼散射研究。纳米双层膜的声子频率随着磁场的变化而发生明显的变化,而单层Pb(Zr,Ti)O3膜则没有这种变化。CoFe 2 O 4层的磁致伸缩产生机械传递到Pb(Zr,Ti)O3层的应力,导致模式变化。观察到的磁场诱导软化的软模式的Pb(Zr,Ti)O3层承担着一个惊人的相似的直接磁电输出的双层,提供证据的应力介导的磁电耦合机制的多铁性双层。
2D magnetoelectric multiferroics in MnSTe/In2Se3 heterobilayer with ferroelectrically controllable skyrmions
磁电效应和Skyrmions是凝聚态物理中的两个基本现象。在这里,使用第一性原理计算和蒙特卡罗模拟,我们提出了强磁电耦合可以证明在一个多铁性异质双层组成的二维(2D)MnSTe和α-In 2 Se 3。通过改变铁电体α-In 2 Se 3的电极化的强度,可以实现拓扑磁相的产生和湮灭,从而产生有趣的铁电可控Skyrmions。进一步揭示了这一特征与D2/ |KJ|的物理量密切相关,它一般适用于描述这种物理所需的条件。系统地讨论了它们的拓扑磁相随温度的变化规律。这些发现不仅极大地丰富了二维磁电多铁性材料的研究,而且为实现新的Skyrmionic器件概念开辟了一条有希望的途径。
Electric susceptibility of antiferromagnetic multiferroics with cycloidal spin order at magnetoelectric effect associated with collinear component of spins
Epitaxial growth of multiferroic Pb(Zr0.57Ti0.43)O3-Pb(Fe2/3W1/3)O3 solid-solution thin films and their magnetoelectric effects
本文报道了用脉冲激光沉积法外延生长单相[Pb(Zr 0.57 Ti 0.43)O3]0.8[Pb(Fe 2/3 W 1/3)O3]0.2(PZT-PFW)固溶体薄膜。X射线衍射测试表明薄膜具有四方晶系结构。该薄膜在室温下表现出铁电性和弱铁磁响应。磁电效应进行了研究,非线性磁电系数进行了测量,发现是可比的多铁性六方锰氧化物,但至少两个数量级小于多晶PZT-PFW薄膜。
Magnetoelectric Phase Diagrams of Multiferroic GdMn2O5
研究了多铁性GdMn_2 O_5在外加磁场中的电磁性质,绘制了该材料的磁电相。由于强磁电耦合,介电常数对GdMn 2 O 5中的相界高度敏感,这允许构建场-温度相图。观察到几个相变是强烈的场依赖于相对于场的方向和强度。沿着晶体学a轴的磁场的相图很好地对应于由Gd磁矩的90度旋转引起的极化步骤。我们的结果支持两个铁电亚晶格,Mn-Mn和Gd-Mn与强R-Mn(4f-3d)相互作用的极化在RMn 2 O 5的模型。
Magnetoelectric training of multiferroic domains in Mn$_2$GeO$_4$
ETH Zurich(苏黎世联邦理工学院);Loughborough University(拉夫堡大学);Paul Scherrer Institut(保罗谢勒研究所);High Energy Accelerator Research Organization (KEK)(高能加速器研究机构);University of Tokyo(东京大学);Norwegian University of Science and Technology (NTNU)(挪威科技大学)
Prediction of new multiferroic and magnetoelectric material Fe3Se4
目前,具有磁电耦合的多铁性材料在新型存储器件领域有着广泛的应用。在室温下制备具有强耦合铁电和亚铁磁有序结构的多铁性材料具有挑战性。硒化铁(Fe_3Se_4)单晶在室温下表现出铁电有序和磁有序共存的II型多铁性。我们研究了铁电金属Fe_3Se_4的晶格不稳定性、电子结构、铁电、亚铁磁有序和输运性质。态密度显示出在费米能级附近Fe-3d和Se-4p态的相当大的杂化,证实了其金属行为。Fe阳离子的磁矩遵循II型亚铁磁和铁电有序,计算出的总磁矩为4.25每晶胞(Fe 6 Se 8)。Fe-Se的强共价键性质导致其铁电性质。此外,对称性分析表明,3d-t2 g轨道有序的Fe亚晶格的倾斜是由于Jahn-Teller(JT)畸变引起的。这项研究为利用多铁性材料发展自旋电子学相关技术提供了进一步的见解。
Multiferroic Properties of Electrospun CFO-BCTSn Nanocomposites for Magnetoelectric and Magnetic Field Sensing Applications
Jozef Stefan Institute(约瑟夫·斯蒂芬研究所);University of Picardie Jules Verne(皮卡第朱尔斯·凡尔纳大学);Cadi-Ayyad University, Faculty of Sciences and Technology(卡迪·阿亚德大学科学与技术学院);University Mohammed VI Polytechnic (UM6P)(穆罕默德六世理工大学);Aix-Marseille University - CNRS(艾克斯-马赛大学-法国国家科学研究中心);Institute of Physics AS CR(捷克科学院物理研究所)
Magnetoelectric effect in multiferroic metals via a direct spin-charge interaction
Key Lab of advanced optoelectronic quantum architecture and measurement (MOE), and School of Interdisciplinary Science, Beijing Institute of Technology(北京理工大学光电量子架构与测量教育部重点实验室,交叉科学研究院)
Simultaneously Magnetic- and Electric-dipole Active Spin Excitations Govern the Static Magnetoelectric Effect in Multiferroic Materials
我们推导出一个求和规则,证明静态磁电(ME)效应是由光学跃迁,同时激发通过光的电和磁分量。通过对磁点群的系统分析,我们证明了ME求和规则适用于包括ME多铁性化合物在内的各种非中心对称磁体。由于动态ME效应,这些材料中的光学激发可以表现出方向二向色性,即对于反向传播的光束,吸收系数可以不同。根据ME求和规则,材料的线性ME效应的大小主要由其低能光激发的方向二色性决定。应用求和规则的多铁性Ba $_2$ CoGe $_2$ O $_7$,Sr $_2$ CoSi $_2$ O $_7$和Ca $_2$ CoSi $_2$ O $_7$表明,在这些化合物中,静态ME效应主要由GHz-THz光谱范围内的自旋波激发的方向二向色性决定。在此基础上,我们认为,方向二向色性的研究和ME求和规则的应用可以促进具有大静态ME效应的新材料的合成。