Berlin 2015 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
TT: Fachverband Tiefe Temperaturen
TT 70: Correlated Electrons: Spin Systems and Itinerant Magnets – Chiral Magnets (jointly with MA)
TT 70.4: Talk
Wednesday, March 18, 2015, 18:45–19:00, H 3005
Spin chirality flip in Fe1−xCoxSi — •Sven-Arne Siegfried1, Evgeny.V. Altenbayev2,3, Nadezhda M. Chubova2,3, Vadim Dyadkin4,2, Dirk Menzel5, Charles D. Dewhurst6, André Heinemann1, Dimitry Chernyshov4, Ravil A. Sadykov7,8, Sergey N. Axenov7, Ludmila N. Formicheva8, Anatoly V. Tsvyashchenko8, Andreas Schreyer1, and Sergey V. Grigoriev2,3 — 1Helmholtz-Zentrum Geesthacht, Germany. — 2Petersburg Nuclear Physics Institute, Russia. — 3Saint- Petersburg State University, Russia. — 4SwissNorwegian Beamlines at ESRF, France. — 5TU Braunschweig, Braunschweig, Germany. — 6Institute Laue-Langevin, France. — 7Institute for Nuclear Research, Russia. — 8Institute for High Pressure Physics,Russia.
Recently the experimental evidence was given for the flip of the spin helix chirality in the two Fe-based germanide compounds Mn1−xFexGe [1] and Fe1−xCoxGe [2]. In this talk we report the similar effect for the Fe-based silicide Fe1−xCoxSi at a critical concentration xc. We have synthesized single-crystalline Fe1−xCoxSi compounds with x running from 0.5 to 0.7 via Czochralski-method. SQUID magnetization measurements have shown the magnetic ordering of all these samples below Tc. At the critical concentration xc ≈ 0.65 we observed a transformation of the helical structure to a ferromagnetic one ( | ks | → 0 ). Polarized small-angle neutron scattering revealed the different sign of the spin helicity for compounds with x > xc and x < xc.
[1] S.V. Grigoriev et al.,PRL. 110, 207201 (2013).
[2] S.V. Grigoriev et al.,PRB 90, 174414 (2014).