Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 28: Correlated Electrons: Spin Systems, Itinerant Magnets 3

TT 28.10: Vortrag

Dienstag, 12. März 2013, 12:00–12:15, H19

Magnetic properties of Mn_1−xFe_xGe — •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 Mn_1−xFe_xGe 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.