Low temperature incommensurately modulated and noncollinear spin structure in FeCr2S4
2010 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 22, no 5, 052205- p.Article in journal (Refereed) Published
FeCr2S4 orders magnetically at T-N approximate to 170 K. According to neutron diffraction, the ordered state down to 4.2 K is a simple collinear ferrimagnet maintaining the cubic spinel structure. Later studies, however, claimed trigonal distortions below similar to 60 K coupled to the formation of a spin glass type ground state. To obtain further insight, muon spin rotation/relaxation (mu SR) spectroscopy was carried out between 5 and 200 K together with new Fe-57 Mossbauer measurements. Below similar to 50 K, our data point to the formation of an incommensurately modulated noncollinear spin arrangement like a helical spin structure. Above 50 K, the spectra are compatible with collinear ferrimagnetism, albeit with a substantial spin disorder on the scale of a few lattice constants. These spin lattice distortions become very large at 150 K and the magnetic state is now better characterized as consisting of rapidly fluctuating short-range ordered spins. The Neel transition is of second order, but ill defined, extending over a range of similar to 10 K. The Mossbauer data around 10 K confirm the onset of orbital freezing and are also compatible with the noncollinear order of iron. The absence of a major change in the quadrupole interaction around 50 K renders the distortion of crystal symmetry to be small.
Place, publisher, year, edition, pages
2010. Vol. 22, no 5, 052205- p.
Physical Sciences Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-137823DOI: 10.1088/0953-8984/22/5/052205ISI: 000273730300005OAI: oai:DiVA.org:uu-137823DiVA: diva2:379252