Microwave conductivity of ferroelectric domains and domain walls in a hexagonal rare-earth ferrite

A complex domain structure with variations in the morphology is observed at ambient temperature in monoclinic Pb(Fe1/2Nb1/2)O3. Using electron microscopy and piezoresponse force microscopy, it is possible to reveal micrometre-sized wedge, lamellar-like, and irregularly shaped domains. By increasing the temperature, the domain structure persists up to 80 °C, and then starts to disappear at around 100 °C due to the proximity of the ferroelectric–paraelectric phase transition, in agreement with macroscopic dielectric measurements. In order to understand to what degree domain switching can occur in the ceramic, the mobility of the domain walls was studied at ambient temperature. The in situ poling experiment performed using piezoresponse force microscopy resulted in an almost perfectly poled area, providing evidence that all types of domains can be easily switched. By poling half an area with 20 V and the other half with −20 V, two domains separated by a straight domain wall were created, indicating that Pb(Fe1/2Nb1/2)O3 is a promising material for domain-wall engineering.

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Synchrotron X-Ray Topographic Study of Defects in High Quality, Flux Grown Ktiopo4 Single Crystals

MRS Proceedings ◽

10.1557/proc-307-243 ◽

1993 ◽

Vol 307 ◽

Author(s):

S. Wang ◽

M. Dudley ◽

L. K. Cheng ◽

J. D. Bierlein

Keyword(s):

Detailed Analysis ◽

Single Crystals ◽

Domain Walls ◽

Defect Structures ◽

Growth Sector ◽

High Quality ◽

X Ray ◽

Free Region ◽

Ferroelectric Domains ◽

Section Topography

ABSTRACTDefect structures in large, high quality flux-grown KTP single crystals have been studied by using synchrotron white beam X-ray topography. Growth dislocations, inclusions, growth sector boundaries, growth bands and surface micro-scratches were imaged. A number of planar defects in the dislocation-free region are imaged and determined to be inversion twin lamellae (lamellar ferroelectric domains) which have never been previously reported in KTP crystals. These inversion twin lamellae were also studied by section topography. Detailed analysis of observed contrast revealed that the domain walls bounding the lamellae are faulted with a fault vector of ½[0±1±1]. This fault vector seems to be consistent with the atomic structure of KTP. A detailed analysis is presented and discussed.

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Stiffness in vortex—like structures due to chirality-domains within a coupled helical rare-earth superlattice

Scientific Reports ◽

10.1038/srep19315 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 5

Author(s):

Amitesh Paul

Keyword(s):

Rare Earth ◽

Domain Walls ◽

Topological Defects ◽

Magnetic Ordering ◽

Direct Consequence ◽

Magnetic Vortex ◽

Range Magnetic Order ◽

Wide Range ◽

Out Of Plane ◽

The Stability

Abstract Vortex domain walls poses chirality or ‘handedness’ which can be exploited to act as memory units by changing their polarity with electric field or driving/manupulating the vortex itself by electric currents in multiferroics. Recently, domain walls formed by one dimensional array of vortex—like structures have been theoretically predicted to exist in disordered rare-earth helical magnets with topological defects. Here, in this report, we have used a combination of two rare-earth metals, e.g."Equation missing" superlattice that leads to long range magnetic order despite their competing anisotropies along the out-of-plane (Er) and in-plane (Tb) directions. Probing the vertically correlated magnetic structures by off-specular polarized neutron scattering we confirm the existence of such magnetic vortex—like domains associated with magnetic helical ordering within the Er layers. The vortex—like structures are predicted to have opposite chirality, side—by—side and are fairly unaffected by the introduction of magnetic ordering between the interfacial Tb layers and also with the increase in magnetic field which is a direct consequence of screening of the vorticity in the system due to a helical background. Overall, the stability of these vortices over a wide range of temperatures, fields and interfacial coupling, opens up the opportunity for fundamental chiral spintronics in unconventional systems.

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