Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 53: Magnetic Heuslers, half-metals and oxides

MA 53.5: Vortrag

Freitag, 5. April 2019, 10:30–10:45, H33

IrMnGa - a disordered Half-Heusler compound with spin glass ground state — •Johannes Kroder¹, Kaustuv Manna¹, Dominik Krieger¹, Alexandr S. Sukhanov^1,2, Enke Liu¹, Horst Borrmann¹, Walter Schnelle¹, Johannes Gooth¹, Dmytro S. Inosov^1,2, Gerhard H. Fecher¹, and Claudia Felser¹ — ¹Max Planck Institut für chemische Physik fester Stoffe, Dresden, Germany — ²Institut für Festkörper- und Materialphysik, Technische Universität Dresden, Dresden, Germany

Heusler compounds with heavy atoms often have interesting non-collinear magnetic structures. We therefore studied the magnetic, structural and transport properties of IrMnGa, which crystallizes within the ordinary Half-Heusler space group 216 but with some disorder. The comparison of neutron and X-ray diffraction experiments indicate that the compounds forms a Y structure (prototype LiMgPdSn). Manganese atoms distribute on two non-equivalent sites, which causes competing exchange interactions and prevents the establishment of long-range magnetic order. Instead, magnetization and AC susceptibility measurements reveal typical spin glass behavior at low temperatures. This involves for example the formation of uniaxial anisotropy during field cooling and the observation of the memory effect. Furthermore, the AC susceptibility shows a sharp cusp at the freezing temperature, whose shift as function of AC frequency can be described by the Vogel-Fulcher law and a critical scaling approach. Our work demonstrates that IrMnGa is the first canonical spin glass within the group of Half-Heusler compounds.