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Identification of inversion domains in KTiOPO4 via resonant X-ray diffraction.

Fabrizi F, Thomas PA, Nisbet G, Collins SP - Acta Crystallogr A Found Adv (2015)

Bottom Line: A novel method is presented for the identification of the absolute crystallographic structure in multi-domain polar materials such as ferroelectric KTiOPO4.This allows one to map the spatial domain distribution in a periodically inverted sample, with a resolution of ∼1 µm achieved with a microfocused beam.This non-contact, non-destructive technique is well suited for samples of large dimensions (in contrast with traditional resonant X-ray methods based on diffraction from Friedel pairs), and its potential is particularly relevant in the context of physical phenomena connected with an absence of inversion symmetry, which require characterization of the underlying absolute atomic structure (such as in the case of magnetoelectric coupling and multiferroics).

View Article: PubMed Central - HTML - PubMed

Affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, England.

ABSTRACT
A novel method is presented for the identification of the absolute crystallographic structure in multi-domain polar materials such as ferroelectric KTiOPO4. Resonant (or 'anomalous') X-ray diffraction spectra collected across the absorption K edge of Ti (4.966 keV) on a single Bragg reflection demonstrate a huge intensity ratio above and below the edge, providing a polar domain contrast of ∼270. This allows one to map the spatial domain distribution in a periodically inverted sample, with a resolution of ∼1 µm achieved with a microfocused beam. This non-contact, non-destructive technique is well suited for samples of large dimensions (in contrast with traditional resonant X-ray methods based on diffraction from Friedel pairs), and its potential is particularly relevant in the context of physical phenomena connected with an absence of inversion symmetry, which require characterization of the underlying absolute atomic structure (such as in the case of magnetoelectric coupling and multiferroics).

No MeSH data available.


Related in: MedlinePlus

Low-resolution maps of the diffraction intensity on the reflection (417) at (a) E = 4.96 keV and (b) E = 5.007 keV (beam spot ∼ 0.015 × 0.05 mm), measured on the same surface of the sample (configuration ‘down’). The energy spectra in Fig. 1 ▸ have been collected in the monodomain region in the top part of the sample (black dots), while the high-resolution maps in Fig. 3 ▸ have been collected in the periodically domain-inverted region (enclosed in black squares).
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fig2: Low-resolution maps of the diffraction intensity on the reflection (417) at (a) E = 4.96 keV and (b) E = 5.007 keV (beam spot ∼ 0.015 × 0.05 mm), measured on the same surface of the sample (configuration ‘down’). The energy spectra in Fig. 1 ▸ have been collected in the monodomain region in the top part of the sample (black dots), while the high-resolution maps in Fig. 3 ▸ have been collected in the periodically domain-inverted region (enclosed in black squares).

Mentions: A low-resolution map of the spatial distribution of domains was obtained by rastering the sample aligned on said reflection at the two different energies below and above the edge (E = 4.96 and 5.007 keV), where the energy above the edge has been specifically chosen to correspond to an intensity of almost zero, in order to enhance the contrast between domains. At this stage the beam was defocused (with both main mirrors and KB mirrors out) and the beam spot was defined by the sample slits to be 0.015 × 0.05 mm. The results are plotted in Fig. 2 ▸. The main feature to be observed is that there is a large monodomain region on the top part of the sample, which can be appreciated by its homogeneous intensity and the contrast above and below the edge.


Identification of inversion domains in KTiOPO4 via resonant X-ray diffraction.

Fabrizi F, Thomas PA, Nisbet G, Collins SP - Acta Crystallogr A Found Adv (2015)

Low-resolution maps of the diffraction intensity on the reflection (417) at (a) E = 4.96 keV and (b) E = 5.007 keV (beam spot ∼ 0.015 × 0.05 mm), measured on the same surface of the sample (configuration ‘down’). The energy spectra in Fig. 1 ▸ have been collected in the monodomain region in the top part of the sample (black dots), while the high-resolution maps in Fig. 3 ▸ have been collected in the periodically domain-inverted region (enclosed in black squares).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487424&req=5

fig2: Low-resolution maps of the diffraction intensity on the reflection (417) at (a) E = 4.96 keV and (b) E = 5.007 keV (beam spot ∼ 0.015 × 0.05 mm), measured on the same surface of the sample (configuration ‘down’). The energy spectra in Fig. 1 ▸ have been collected in the monodomain region in the top part of the sample (black dots), while the high-resolution maps in Fig. 3 ▸ have been collected in the periodically domain-inverted region (enclosed in black squares).
Mentions: A low-resolution map of the spatial distribution of domains was obtained by rastering the sample aligned on said reflection at the two different energies below and above the edge (E = 4.96 and 5.007 keV), where the energy above the edge has been specifically chosen to correspond to an intensity of almost zero, in order to enhance the contrast between domains. At this stage the beam was defocused (with both main mirrors and KB mirrors out) and the beam spot was defined by the sample slits to be 0.015 × 0.05 mm. The results are plotted in Fig. 2 ▸. The main feature to be observed is that there is a large monodomain region on the top part of the sample, which can be appreciated by its homogeneous intensity and the contrast above and below the edge.

Bottom Line: A novel method is presented for the identification of the absolute crystallographic structure in multi-domain polar materials such as ferroelectric KTiOPO4.This allows one to map the spatial domain distribution in a periodically inverted sample, with a resolution of ∼1 µm achieved with a microfocused beam.This non-contact, non-destructive technique is well suited for samples of large dimensions (in contrast with traditional resonant X-ray methods based on diffraction from Friedel pairs), and its potential is particularly relevant in the context of physical phenomena connected with an absence of inversion symmetry, which require characterization of the underlying absolute atomic structure (such as in the case of magnetoelectric coupling and multiferroics).

View Article: PubMed Central - HTML - PubMed

Affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, England.

ABSTRACT
A novel method is presented for the identification of the absolute crystallographic structure in multi-domain polar materials such as ferroelectric KTiOPO4. Resonant (or 'anomalous') X-ray diffraction spectra collected across the absorption K edge of Ti (4.966 keV) on a single Bragg reflection demonstrate a huge intensity ratio above and below the edge, providing a polar domain contrast of ∼270. This allows one to map the spatial domain distribution in a periodically inverted sample, with a resolution of ∼1 µm achieved with a microfocused beam. This non-contact, non-destructive technique is well suited for samples of large dimensions (in contrast with traditional resonant X-ray methods based on diffraction from Friedel pairs), and its potential is particularly relevant in the context of physical phenomena connected with an absence of inversion symmetry, which require characterization of the underlying absolute atomic structure (such as in the case of magnetoelectric coupling and multiferroics).

No MeSH data available.


Related in: MedlinePlus