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MA: Fachverband Magnetismus
MA 51: Caloric Effects in Ferromagnetic Materials
MA 51.6: Talk
Friday, March 22, 2024, 11:00–11:15, H 2013
Direct measurements of the adiabatic temperature change in a holmium single crystal using high magnetic fields — •E. Bykov1, C. Salazar Mejia1, T. Gottschall1, J. Wosnitza1,2, M. D. Kuz’min3, Y. Mudryk4, and D. L. Schlagel4 — 1Hochfeld-Magnetlabor Dresden (HLD-EMFL), HZDR, Dresden, Germany — 2Technische Universität Dresden, Dresden, Germany — 3Aix-Marseille Université, IM2NP, Marseille, France — 4Ames Laboratory, U.S. Department of Energy, Iowa State University, Ames, USA
Holmium stands out as an extraordinary magnetocaloric substance due to one of the most substantial magnetic moments found in the periodic table. Its magnetic behavior under temperature and magnetic field variation is intricate, as reflected in a complex phase diagram featuring paramagnetic, helicoidal, conical, fan, spin-slip, and ferromagnetic phases. Even with field variations of 5 T along its easy axis, holmium exhibits a robust magnetocaloric effect, showcasing Δ Tad of approximately 5 K and Δ ST ≈ -10 J kg−1 K−1 across a wide temperature span from 20 to 100 K. This positions holmium as a promising material for refrigeration in an active magnetic regenerator system, particularly for applications such as natural gas and hydrogen liquefaction. We present the results of a comprehensive study of single-crystalline holmium in fields up to 60 T.
Keywords: rare earth; magnetic cooling; high magnetic fields; hydrogen liqufaction