Direct imaging of the structural domains in the iron pnictides AFe[subscript 2]As[subscript 2] (A=Ca, Sr, Ba)
The parent compounds of recently discovered iron-arsenide superconductors, AFe{sub 2}As{sub 2} with alkaline earth A=Ca,Sr,Ba, undergo simultaneous structural and magnetic phase transitions at a temperature T{sub SM}. Using a combination of polarized light microscopy and spatially resolved high-energy synchrotron x-ray diffraction we show that the orthorhombic distortion leads to the formation of 45{sup o}-type structural domains in all parent compounds. Domains penetrate through the sample thickness in the c direction and are not affected by crystal imperfections such as growth terraces. The domains form regular stripe patterns in the plane with a characteristic dimension of 10--50 {mu}m. The direction of the stripes is fixed with respect to the tetragonal (100) and (010) directions but can change by 90{sup o} on thermal cycling through the transition. This domain pattern may have profound implications for intrinsic disorder and anisotropy of iron arsenides.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1005709
- Journal Information:
- Phys. Rev. B, Vol. 79, Issue 2009; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- ENGLISH
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