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We present an ab initio study of the BFCO solid solution formed by multiferroics BiFeO3 (BFO) and BiCoO3 (BCO). We find that BFCO presents a strongly discontinuous morphotropic transition between BFO-like and BCO-like ferroelectric phases.…

材料科学 · 物理学 2011-08-23 Oswaldo Diéguez , Jorge Íñiguez

Piezoelectrics interconvert mechanical energy and electric charge and are widely used in actuators and sensors. The best performing materials are ferroelectrics at a morphotropic phase boundary (MPB), where several phases can intimately…

The classical Heisenberg antiferromagnet with uniaxial exchange anisotropy, the XXZ model, and competing planar single-ion anisotropy in a magnetic field on a simple cubic lattice is studied with the help of extensive Monte Carlo…

统计力学 · 物理学 2015-06-12 Walter Selke

High-frequency dielectric studies of Bi_0.85Nd_0.15FeO_3 ceramics performed betweeen 100 and 900 K reveal hardening of most polar phonons on cooling below antiferroelectric phase transition, which occurs near 600 K. Moreover, a strong THz…

材料科学 · 物理学 2011-10-18 V. Goian , S. Kamba , S. Greicius , D. Nuzhnyy , S. Karimi , I. M. Reaney

Antiferroelectrics are emerging as advanced functional materials and are fertile ground for unusual electric effects. For example, they enhance the recoverable energy density in energy storage applications and give rise to large…

We present the results of the high-temperature neutron and x-ray diffraction experiments on the Ca3-xSrxTi2O7 (x = 0.5, 0.8, 0.85, 0.9) compounds. The ferro- to paraelectric transition in these hybrid improper ferroelectric materials arises…

We have successfully induced multiferroic behavior in the A-type antiferromagnet SmMnO3 by the substitution of Y at the Sm site. A magnetic transition develops at 24 K for Sm1-xYxMnO3 (x=0.4,0.5) which is not present in the parent compound.…

强关联电子 · 物理学 2011-05-17 D. O'Flynn , C. V. Tomy , M. R. Lees , A. Daoud-Aladine , G. Balakrishnan

Observations by in-situ transmission electron microscopy (TEM) reveal the changes in domains morphology in 0.885(Bi1/2Na1/2)TiO3-0.05(Bi1/2K1/2)TiO3-0.015(Bi1/2Li1/2)TiO3-0.05BaTiO3 ceramics. Evolution of the macroscopic ferroelectric…

材料科学 · 物理学 2011-03-31 Cheuk W. Tai , S. H. Choy , H. L. W. Chan

Antiferroelectrics have been recently sparking interest due to their potential use in energy storage and electrocaloric cooling. Their main distinctive feature is antiferroelectric switching, i.e. the possibility to induce a phase…

The nanostructural evolution of the strain-induced structural phase transition in BiFeO3 is examined. Using high-resolution X-ray diffraction and scanning-probe microscopy-based studies we have uniquely identified and examined the numerous…

材料科学 · 物理学 2011-05-23 A. R. Damodaran , C. -W. Liang , Q. He , C. -Y. Peng , L. Chang , Y. -H. Chu , L. W. Martin

Competing interactions and geometric frustration provide favourable conditions for exotic states of matter. Such competition often causes multiple phase transitions as a function of temperature and can lead to magnetic structures that break…

In this paper, we present a microscopic model for heterogeneous ferroelectric and an order parameter for relaxor phase. We write a Landau theory based on this model and its application to ferroelectric PbFe$_{1/2}$Ta$_{1/2}$O$_3$ (PFT) and…

材料科学 · 物理学 2009-11-10 S. A. Prosandeev , I. P. Raevski , U. V. Waghmare

We report a high resolution neutron diffraction investigation of the coupling of structural and magnetic transitions in Ba1xKxFe2As2. The tetragonal-orthorhombic and antiferromagnetic transitions are suppressed with potassium-doping,…

Resistivity measurements are widely exploited to uncover electronic excitations and phase transitions in metallic solids. While single crystals are preferably studied to explore crystalline anisotropies, these usually cancel out in…

Understanding the polarization switching mechanisms at play in ferroelectric materials is crucial for their exploitation in electronic devices. The conventional centrosymmetric reference structure-based mechanism which accounts for…

We report direct experimental evidence of antiferroelectric to paraelectric phase transition under pressure in NaNbO3 using neutron diffraction at room temperature. The paraelectric phase is found to stabilize above 8 GPa and its crystal…

材料科学 · 物理学 2015-06-11 S. K. Mishra , M. K. Gupta , R. Mittal , S. L. Chaplot , Thomas Hansen

The effect of the octahedral tilting of ASnO3 (A = Ca, Sr, Ba) parent compound and bi-color ASnO3/BSnO3 superlattice (A, B = Ca, Sr, Ba) was predicted from density-functional theory. In the ASnO3 parent compound, the structural phase…

材料科学 · 物理学 2016-06-06 Hyunsu Sim , S. W. Cheong , Bog G. Kim

The phase diagram of the prototype antiferroelectric liquid crystal MHPOBC in dependence of enantiomeric excess was measured. It was shown that the SmCbeta phase in very pure samples is the SmCFI2 phase with a four layer structure, and only…

软凝聚态物质 · 物理学 2007-05-23 E. Gorecka , D. Pociecha , M. Cepic , B. Zeks , R. Dabrowski

Low-energy antiferromagnetic phase transitions offer an appealing platform for low-power spintronic functionalities, yet their direct electrical access in insulating antiferromagnets remains challenging, particularly in the low-field regime…

Density functional calculations are performed to investigate the experimentally-reported field-induced phase transition in thin-film ZrO2 (J. Muller et al., Nano. Lett. 12, 4318). We find a small energy difference of ~ 1 meV/f.u. between…

材料科学 · 物理学 2014-10-22 Sebastian E. Reyes-Lillo , Kevin F. Garrity , Karin M. Rabe