Berlin 2015 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 24: Magnetic Materials I
MA 24.4: Vortrag
Mittwoch, 18. März 2015, 10:15–10:30, H 0112
The magnetocaloric effect in transition metal borides — •Maximilian Fries1, Konstantin Skokov1, Michael Kuzmin2, Zsolt Gercsi3, and Oliver Gutfleisch1 — 1Technische Universität Darmstadt — 2Faculté des Sciences et Techniques Marseille — 3Trinity College Dublin
Magnetic cooling is a thriving research topic because it may offer considerably higher energy efficiency compared to traditional vapor compression based machines. In a reverse process the magnetocaloric effect can also be utilized in a thermoelectric generator. In order to make these technologies viable, material compositions with highly tunable Curie Temperatures (TC) in the range of 200-600K are needed.
The group of transition metal borides may be a good candidate especially for high temperature applications, as they are chemically inert and stable in air even at elevated temperatures. Many Borides exhibit high magnetic moments for example like pure MnB which exhibits the highest magnetization of all 3d metal monoborides with 158 emu/g.
Here we will report on transition metal borides based on Cobalt, Manganese and Iron. We will show and discuss the magnetic, magnetocaloric and structural properties including spontaneous magnetization, entropy change and lattice expansion. The results are complemented with insights from theory based on DFT calculations.