As known, there is strip-like AFM ordering in pnictides RFeAsO or RFe2As2: Fe moments are parallel along a, but antiparallel along b in ab plane. But the orthorhombic structure is twin. In the twin domains, are the AFM magnetic orderings exactly the same or not? I plotted two cases of the strip-like AFM ordering in the attachment. Which picture is correct, (a) or (b)?
If picture (b) is correct, is the observed magnetic Bragg peak, like (120) in ab plane and (101) in ac plane by neutron diffraction the information from only one domain or the sum of twin domain?
If your structure is tetragonal you will in general see the contributions of the two twin domains. If you have orthorhombic distortion as I remember at least for EuFe2As2 then you might have a chance to have a single domain sample. If the distortions are small in neutron diffraction you are likely to measure the contribution of the two twins. An appealing alternative is to measure with X-rays as they have better resolution in reciprocal space and therefore the domains can (with some luck) be separated. You may want to look at the magnetic structure of EuFe2As2 (PHYSICAL REVIEW B 80, 134411 ). As far as I remember there were no twins there due to the orthorhombic distortion.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Inorganic Materials
- Metals
- Alloys
- Steel