Berlin 2018 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 38: Magnetocaloric Effects (joint session MA/TT)
TT 38.6: Talk
Tuesday, March 13, 2018, 10:45–11:00, EB 407
Correlation of microstructural and magnetic properties of Mn-Fe-P-Si magnetocaloric compounds — •Lukas Pfeuffer1, Maximilian Fries1, Enrico Bruder1, Tino Gottschall2, Semih Ener1, Léopold Diop1, Thorsten Gröb1, Konstantin Skokov1, and Oliver Gutfleisch1 — 1Fachbereich Materialwissenschaft, TU Darmstadt, 64287, Darmstadt, Germany — 2Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
Mn-Fe-P-Si alloys of Fe2P-type are very promising candidates for magnetocaloric applications. Extensive studies dealing with the optimization of the chemical composition have been published in recent years. However, the microstructure and its effect on the thermomagnetic properties are rarely discussed in literature. For this reason, we processed Mn-Fe-P-Si samples using a powder-metallurgical approach and characterized their microstructure and magnetocaloric behaviour. SEM, EDX, EBSD and XRD studies display small amounts of a cubic secondary phase showing a distinct phosphorous depletion and a characteristic arrangement at the triple junctions of the Fe2P grains. A shift in saturation magnetization, transition temperature and isothermal entropy change as a function of the secondary phase fraction can be observed. A significant influence of the metal/non-metal ratio on the above mentioned properties could be investigated. Additionally, all the prepared samples reveal a virgin effect shown thermomagnetically and with temperature dependent optical microscopy.