The origin of the polar symmetry in huebnerite-type multiferroics

Polar conductors/superconductors with Rashba-type spin-orbit interaction are potential material platforms for quantum transport and spintronic functionalities. One of their inherent properties is the nonreciprocal transport, where the rightward and leftward currents become inequivalent, reflecting spatial inversion/time-reversal symmetry breaking. Such a rectification effect originating from the polar symmetry has been recently observed at interfaces or bulk Rashba semiconductors, while its mechanism in a polar superconductor remains elusive. Here, we report the nonreciprocal transport in gate-induced two-dimensional superconductor SrTiO3, which is a Rashba superconductor candidate. In addition to the gigantic enhancement of nonreciprocal signals in the superconducting fluctuation region, we found kink and sharp peak structures around critical temperatures, which reflect the crossover behavior from the paraconductivity origin to the vortex origin, based on a microscopic theory. The present result proves that the nonreciprocal transport is a powerful tool for investigating the interfacial/polar superconductors without inversion symmetry, where rich exotic features are theoretically prognosticated.

Download Full-text

HP/HT synthesis and characterization of novel multiferroic Bi-based perovskites

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314081856 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1815-C1815

Author(s):

Davide Delmonte ◽

Francesco Mezzadri ◽

Chiara Pernechele ◽

Massimo Solzi ◽

Gianluca Calestani ◽

...

Keyword(s):

Data Storage ◽

Lone Pair ◽

Solid State Reactions ◽

Crystallographic Structure ◽

Scientific Publications ◽

Increasing Trend ◽

Magnetic Ions ◽

Oxygen Anions ◽

Polar Symmetry

Bi-based perovskites (BiM1-xM'xO3, where M e M' are 3d and 4d metal ions) are considered very promising candidates to show multiferroic magnetoelectric character. A multiferroic magnetoelectric is a material in which ferromagnetism and ferroelectricity are not only coexistent but also coupled. Such properties, very rare in natural materials, are suitable for electronics, data storage and spintronics applications. Therefore, the interest in this class of compound showed an increasing trend of scientific publications in the last ten years. Unfortunately most members of this family cannot be synthesized with conventional techniques, due to their highly unstable and distorted crystallographic structure. High isostatic pressures and high temperatures can be exploited to overcome this fundamental drawback. The strategy is to induce ferroelectricity (e.g. polar symmetry) achieving the stereochemical effect of Bi3+ 6s2 lone pair, that polarizes the bonds with the neighboring oxygen anions, and independently to bring magnetism through the introduction of magnetic ions of the third or the fourth period on the octahedral coordinated B-site of the perovskite structure. We have synthesized simple and complex (quadruple [1,2] and double [3]) Bi-based perovskites in wide ranges of pressure (from 3 to 9 GPa) and temperature (from 9000C to 16500C) by means of solid state reactions in a multi-anvil Walker-type Press. We present an accurate study of the structural, magnetic and electric properties. Furthermore, unconventional home-made set-ups are also presented as the tools to probe the coupling between the electric and the magnetic properties through crossed magnetic characterizations (magnetic susceptibility dependence on an applied electric field) and reversely crossed electric characterizations (polarization as a function of an external magnetic field).

Download Full-text

Thermal Stress Analysis of Pin Grid Array Structures: Module and Card Interactions

Journal of Electronic Packaging ◽

10.1115/1.2905458 ◽

1992 ◽

Vol 114 (3) ◽

pp. 322-328 ◽

Cited By ~ 4

Author(s):

P. A. Engel ◽

J. R. Webb

Keyword(s):

Thermal Stress ◽

Stress Analysis ◽

Stress Relief ◽

Force Measurements ◽

Force System ◽

Thermal Stress Analysis ◽

Collocation Technique ◽

Plate Equations ◽

Array Structures ◽

Polar Symmetry

While primary thermal stress analysis of pin grid arrays considers a nonflexible card and module delineating the structure, in this paper we consider the stress relief (resulting in a “secondary” force system) afforded by bending and stretching of the delineating plates. The primary axial force F, plate moments, M1, M2, and shear V are considered acting in radial planes, and the secondary pin forces P are solved by stipulating compatibility of deformations at the two pin ends. A collocation technique is used to evaluate the plate equations in polar symmetry. The contributions of transverse plate compliances, and in-plane compliances are evaluated numerically for a 50 mm ceramic module, and compared with known experimental force measurements.

Download Full-text

polar symmetry

Dictionary of Gems and Gemology ◽

10.1007/978-3-540-72816-0_17207 ◽

2009 ◽

pp. 678-678

Keyword(s):

Polar Symmetry

Download Full-text

A New Wavefront Sensor With Polar Symmetry: Quantitative Comparisons With a Shack-Hartmann Wavefront Sensor

Journal of Refractive Surgery ◽

10.3928/1081-597x-20061101-23 ◽

2006 ◽

Vol 22 (9) ◽

pp. 954-958

Author(s):

Luis Alberto Carvalho ◽

Jarbas Castro ◽

Wallace Chamon ◽

Paulo Schor

Keyword(s):

Wavefront Sensor ◽

Polar Symmetry

Download Full-text

Seven-Set Venn Diagrams with Rotational and Polar Symmetry

Combinatorics Probability Computing ◽

10.1017/s0963548397003143 ◽

1998 ◽

Vol 7 (2) ◽

pp. 149-152 ◽

Cited By ~ 7

Author(s):

A. W. F. EDWARDS

Keyword(s):

Venn Diagrams ◽

Polar Symmetry

Download Full-text

Polar Symmetry and Intercalation of New Multilayered Hybrid Molybdates: [M2(pzc)2(H2O)x][Mo5O16] (M = Co, Ni)

Inorganic Chemistry ◽

10.1021/ic060253e ◽

2006 ◽

Vol 45 (12) ◽

pp. 4721-4727 ◽

Cited By ~ 10

Author(s):

Bangbo Yan ◽

Paul A. Maggard

Keyword(s):

Polar Symmetry

Download Full-text

The POLICRYPS liquid-crystalline structure for optical applications

Advanced Optical Technologies ◽

10.1515/aot-2018-0027 ◽

2018 ◽

Vol 7 (5) ◽

pp. 273-289

Author(s):

Roberto Caputo ◽

Antonio De Luca ◽

Giuseppe Strangi ◽

Roberto Bartolino ◽

Cesare Umeton ◽

...

Keyword(s):

Liquid Crystal ◽

Soft Matter ◽

Liquid Crystalline ◽

High Efficiency ◽

Light Polarization ◽

Polymer Liquid ◽

Polarized Beams ◽

Optical Applications ◽

Polar Symmetry ◽

Polymer Liquid Crystal

Abstract We present a review of polymer-liquid crystal-based devices for optical applications. Starting from a particular fabrication technique, which enables to obtain the POLICRYPS (POlymer LIquid CRYstal Polymer Slices) structure, we illustrate different realizations, along with their working principle and main features and performances. The name POLICRYPS indicates a structure made of parallel slices of pure polymeric material alternated to films of well-aligned nematic liquid crystal (NLC), with a spatial periodicity that can be settled in the range 0.2÷15 μm. Suitably designed samples can be utilized as optical devices with a high efficiency, which can be switched on and off both by applying an electric field of a few V/μm or by irradiating samples with a suitable light beam. In different geometries, POLICRYPS can be specialized to operate as switchable diffraction grating, switchable optical phase modulator, switchable beam splitter, or tunable Bragg filter. The POLICRYPS framework can be also used as a soft matter template for aligning different types of LCs or to create an array of tunable microlasers. Finally, we present a POLICRYPS structure with a polar symmetry of the director alignment, which enables local shaping of light polarization, allowing to convert circularly polarized beams into cylindrical vector beams.

Download Full-text