Dresden 2026 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 30: Caloric Effects in Ferromagnetic Materials (joint session MA/TT)

TT 30.7: Vortrag

Dienstag, 10. März 2026, 11:15–11:30, POT/0151

Frustration and Antiferromagnetic Ordering in Low-Temperature Materials for Adiabatic Demagnetization — •Anton Jesche, Tim Treu, Marvin Klinger, Jorginho Villar Guerrero, and Philipp Gegenwart — EP VI, Institute of Physics, University of Augsburg, Germany

The development of improved materials for adiabatic demagnetization refrigeration (ADR) has been driven increasingly by research on magnetically frustrated systems, where competing interactions can suppress magnetic ordering to very low temperatures [1]. Such behavior is particularly attractive for low-temperature cooling and has led to several promising rare-earth-based compounds. Notable examples include KBaYb(BO₃)₂, which reaches temperatures near 20 mK [2], and NaGdP₂O₇, which demonstrates extended hold times below 2 K in standard cryogenic environments [3].

This contribution will highlight selected Yb- and Gd-based materials and discuss the influence of frustration and antiferromagnetic (AFM) ordering on their cooling performance. Using NaGdP₂O₇ as a representative case, we examine how magnetic entropy near AFM transitions affects ADR behavior under varying magnetic fields and temperatures. We further show that high-resolution thermodynamic information, such as heat capacity, can be extracted directly from ADR curves.

[1] M. E. Zhitomirsky, Phys. Rev. B, 2003, 67, 104421, [2] Y. Tokiwa, Commun. Mater. 2021, 2, 42, [3] P. Telang, Phys. Rev. B, 2025, 111, 064434

Keywords: magnetic frustration; adiabatic demagnetization refrigeration; magnetic cooling; magnetic ordering