Polarized light and X-ray precession study of the ferroelastic domains of YBa2Cu3O7-?

Abstract

The ferroelastic domains of the orthorhombic phase of YBa2Cu307_ 0 have been observed in polarized light on ceramics and single crystals. By combining polarized light microscopy with the X-ray precession technique, the correlation of the orientation of the orthorhombic a-and b-axes with that of the a-b-plane bireflectance, reflection dichroism, transmission dichroism (at a thickness of about 1 pm), reflection tints generated with compensators and upon uncrossing of polars, as well as the orientation of etch pits has been realized on ferroelastic single domains, bi-domains and more complicated domain patterns. Four ferroelastic orthorhombic domain states have been identified, at variance with former group theoretical considerations, predicting only two states. Ensembles of lamellar domains beyond optical resolution generate strong bireflectance with principal axes rotated by 45 ~ relative to the true a, b-directions.

Intrinsic pinning on structural domains in underdoped single crystals ofBa(Fe1−xCox)Prozorov1, Tanatar2, Ni3 et al. 2009Phys. Rev. B116191111View full textAdd to dashboardCite

“…2. The decreasing δ affects the optical contrast, since linearly-polarized light imaging detects the anisotropic optical response of the neighboring twins [25] and the degree of this anisotropy is proportional to δ. This decreases the difference in the light intensity between the twins.…”

βphase andγ−βmetal-insulator transition in multiferroicBiFePalai1, Katiyar2, Schmid3 et al. 2008Phys. Rev. BSelf Cite628443586View full textAdd to dashboardCite

“…The reflectivities and bireflectance values of ␣-BFO have so far not yet been quantitatively characterized, as this has been done, e.g., for YBa 2 Cu 3 O 7+␦ . 57,58 Such a characterization would greatly facilitate work with single crystals and their ferroelastic domains. As an example of the contrast which can be obtained between ferroelastic domains with the principal reflectance in the plane, we show a cross section through a leaf of the fernlike dendrites ͑Fig.…”

Multi-ferroic magnetoelectrics

“…They come into play and become well observable by X-rays when the spontaneous deformation is important, as is e.g. the case in the ortho rhombic, ferroelastic phase of YBa 2 Cu 3 0 7 _x- 24 Before starting to make physical measurements on materials with phase transitions, like multi-ferroics, it is therefore of greatest importance to begin by studying in polarized light the phase transitions, domai n structures and crystal optical prop- -< respectively . Columns 7-9: " full" a nd " P" stand for full and panial coupling of stress, electric field and magnetic field to the ferroelastic, ferroelectric and ferromagnetic domains, respectively.…”