Regensburg 2016 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 23: Magnetic Materials and Caloric Effects
MA 23.2: Vortrag
Dienstag, 8. März 2016, 14:15–14:30, H32
Magnetic phase transitions and their lattice responses in the compound system Mn5-xFexSi3 — •Paul Hering1, Hang Zong1, Ye Cheng1, Karen Friese1, Anatoliy Senyshyn2, and Thomas Brückel1 — 1JCNS-2/PGI4, Forschungszentrum Jülich GmbH — 2MLZ, TUM, Garching
Magnetic cooling based on the magnetocaloric effect could replace conventional vapor compression cooling, as it has a potentially lower energy consumption and does not rely on environmental hazardous gases. The compounds within the system Mn5-xFexSi3 undergo a variety of magnetic phase transitions at different temperatures depending on their iron content which is distributed on at least one mixed Mn/Fe site and one pure iron site [H. Binczyska, at al., Phys. Stat. Sol., Sect. A, 19, 13-17 (1973)]. The corresponding magnetic entropy changes show different shapes and magnitudes ranging from a negative MCE (x=0) to the modestly high positive magnetocaloric effect (MCE) of 2.9 J/kg K at a magnetic field change from 0 T to 2 T (x=4) [Songlin, et al., J. Alloys Comp. 334, 249-252 (2002)]. Therefore, this system is an ideal choice to gain a better understanding of the underlying mechanism of the MCE in multiple site driven magnetocaloric materials. A combination of macroscopic temperature dependent magnetization measurements on polycrystalline and single crystal samples and temperature dependent neutron and x-ray powder diffraction allows the establishment of a magnetic phase diagram of the system. Additionally lattice responses to the transitions were characterized.