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MA: Fachverband Magnetismus

MA 23: Magnetic Materials and Caloric Effects

MA 23.3: Talk

Tuesday, March 8, 2016, 14:30–14:45, H32

Structure and magnetism of single crystal Mn₃GaC — •Franziska Scheibel, Detlef Spoddig, Ralf Meckenstock, Markus E. Gruner, Benjamin Zingsem, Michael Farle, and Mehmet Acet — Faculty of Physics and Center for Nanointegration (CENIDE), University Duisburg-Essen, Lotharstr. 1, 47057 Duisburg

Mn₃GaC undergoes a first-order magnetic transition from an antiferromagnetic to a ferromagnetic phase at T_i and a second-order magnetic transition from the ferromagnetic to the paramagnetic phase at T_C. A large reversible adiabatic temperature-change of Δ T_ad=4.7 K related to an entropy change of Δ S=14 Jkg⁻¹K⁻¹ in 2 T field makes this compound interesting for magnetic refrigeration [1]. The magnetic properties of a 15x15x28 µm single crystal Mn₃GaC were studied using magnetometry and ferromagnetic resonance (FMR). The transition temperatures T_i=163 K T_C=236 K and the saturation magnetization of 0.41 MAm⁻¹ at 200 K agree well with those of polycrystalline material. Temperature and orientation dependent FMR spectra show a dominant shape anisotropy compared to the magnetocrystalline anisotropy (−5±1 kJm⁻³). The {111} direction is identified as the magnetic easy axis. The results are compared to micro magnetic simulations, free energy density and DFT calculations and are found to be in good agreement.
Work supported by the Deutsche Forschungsgemeinschaft (SPP 1599). [1] F. Scheibel et al., J. Appl. Phys. 117 (2015) 233902.