Low temperature incommensurately modulated and noncollinear spin structure in FeCr2S4.
J Phys Condens Matter
; 22(5): 052205, 2010 Feb 10.
Article
en En
| MEDLINE
| ID: mdl-21386336
FeCr(2)S(4) orders magnetically at T(N)≈ 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 â¼ 60 K coupled to the formation of a spin glass type ground state. To obtain further insight, muon spin rotation/relaxation (µSR) spectroscopy was carried out between 5 and 200 K together with new (57)Fe Mössbauer measurements. Below â¼ 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 Néel transition is of second order, but ill defined, extending over a range of â¼ 10 K. The Mössbauer 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.
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01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Phys Condens Matter
Asunto de la revista:
BIOFISICA
Año:
2010
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Reino Unido