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TT: Fachverband Tiefe Temperaturen
TT 28: Correlated Electrons: Spin Systems, Itinerant Magnets 3
TT 28.10: Talk
Tuesday, March 12, 2013, 12:00–12:15, H19
Magnetic properties of Mn1−xFexGe — •Sven-Arne Siegfried1, Nadezhda Potapova2, Evgeny Moskvin2, Vadim Dyadkin3, Dirk Menzel4, Charles D. Dewhurst5, Anatoly V. Tsvyashchenko6, Dieter Lott1, Andreas Schreyer1, and Sergey Grigoriev2 — 1Helmholtz-Zentrum Geesthacht, Geesthacht, Germany. — 2Petersburg Nuclear Physics Institute, Gatchina, Russia. — 3Swiss-Norwegian Beamlines at ESRF, Grenoble, France — 4TU Braunschweig, Braunschweig, Germany — 5Institut Laue-Langevin, Grenoble, France — 6Institute for High Pressure Physics, Troitsk, Russia
The cubic B20 type transition-metal monogermanides belong to the P213 space group. B20 systems order in a helical spin structure which can be transformed by a magnetic field into a conical and even a parallel ferromagnetic configuration. Close to the ordering temperature the so called A-phase exists. Polycrystalline Mn1−xFexGe samples have been synthesized by high pressure method and investigated by SQUID magnetization measurements and small angle neutron scattering. For this compounds the variation of the helical period from 18 nm for MnGe up to 70 nm for FeGe comes along with a change in the ordering temperatures from 170 K up to 280 K. For concentrations below x = 0.5 our SANS patterns at zero field show a temperature dependent decrease of the helical wavelength with increasing temperature. For field dependent measurements different characteristic patterns appears indicating a complex H-T magnetic phase diagram for this compounds.