Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Poster Session: Correlated Electrons 1
TT 17.12: Poster
Montag, 1. April 2019, 15:00–18:30, Poster D
Metallic 4f-electron system with a large magnetic cooling capacity — •Thomas Gruner1, Jiasheng Chen1, Jacintha Banda2, Jang Dongjin3, Manuel Brando2, Christoph Geibel2, and Malte Grosche1 — 1Cavendish Laboratory, University of Cambridge, Cambridge, UK — 2MPI CPfS, Dresden, Germany — 3KRISS, Daejeon, Republic of Korea
All standard cooling materials used in present day demagnetisation refrigerators for the temperature range 50 mK < T < 2 K are insulators, resulting in some problems e.g. because of their very weak low-temperature thermal conductivity. Recently, we proposed and showed that some Yb based metallic materials provide attractive alternatives [1], and ideas which meanwhile has been picked up by further research groups. In a search for even more appropriate materials we have synthesised a new Yb Heusler compound and investigated its structural, magnetic, transport and magnetocaloric properties.
Susceptibility χ(T), magnetisation M(B), specific heat C(T) and resistivity ρ(T) data evidence metallic behaviour, the absence of superconductivity and a stable trivalent Yb3+ state, without any sign for a significant Kondo interaction. Our new compound can easily be cast into rods, making preparation of cooling pills quite simple in contrast to commonly used paramagnetic salt refrigerants. By using a demagnetisation test set-up, we demonstrate the feasibility of a simple, economically priced and durable alternative for traditional cooling devices for temperatures down to roughly 100 mK.
[1] Jang, Gruner et al.; Nature Communications; 6, 8680 (2015)