SKM 2021 – scientific programme

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MA: Fachverband Magnetismus

MA 15: Posters Magnetism IV

MA 15.22: Poster

Thursday, September 30, 2021, 13:30–16:30, P

Magnetocaloric effect in the Ho_1−xDy_xAl₂ family in high magnetic fields — •Eduard Bykov^1,2, Wei Liu³, Konstantin Skokov³, Franziska Scheibel³, Oliver Gutfleisch³, Sergey Taskaev⁴, Catalina Salazar Mejia¹, Joachim Wosnitza^1,2, and Tino Gottschall¹ — ¹Hochfeld-Magnetlabor Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Germany — ²Institut für Festkörper- und Materialphysik, Technische Universität Dresden, Germany — ³Funktionale Materialien, Technische Universität, TU Darmstadt, Germany — ⁴Chelyabinsk State University, Russia

Hydrogen has the largest gravimetric energy density among all chemical fuels. At the same time, the density of gaseous H₂ is extremely low. For storage and transportation reasons it can be liquified. But it requires energy-intensive cooling down to 20 K. Magnetocaloric materials have the great potential to revolutionize gas liquefaction in order to make liquid hydrogen more competitive as fuel. We investigated a series of Laves-phase materials regarding their structural, magnetic, and magnetocaloric properties in high magnetic fields. The three compounds HoAl₂, Ho_0.5Dy_0.5Al₂, and DyAl₂ are suited for building a stack for cooling from liquid-nitrogen temperature (77 K) down to the boiling point of hydrogen at 20 K. This is evident from our direct measurements of the adiabatic temperature change in pulsed magnetic fields, which we compare with calorimetric data measured in static field. With this methodology, we are now able to study the suitability of magnetocaloric materials down to low temperatures up to the highest magnetic fields.