Rotating magnetocaloric effect and unusual magnetic features in metallic strongly anisotropic geometrically frustrated TmB4

• Published in: Scientific reports 2018-07, Vol.8 (1), p.1-10, Article 10933
• Main Authors: Orendáč, Matúš, Gabáni, Slavomír, Gažo, Emil, Pristáš, Gabriel, Shitsevalova, Natalya, Siemensmeyer, Konrad, Flachbart, Karol
• Format: Article
• Language: English
• Subjects: 639/301/1023; 639/766/119; Anisotropy; Entropy; Humanities and Social Sciences; Low temperature; Magnetic fields; multidisciplinary; Refrigeration; Science; Science (multidisciplinary); Temperature effects
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-29399-2

We have investigated the rotating magnetocaloric effect (R-MCE) of TmB 4 - an anisotropic magnetic system with geometrical frustration of Shastry-Sutherland type. The R-MCE was obtained from detailed temperature dependencies of heat capacity in various magnetic fields of a single crystalline sample for crystal axes orientations c || B and c ⊥ B . The received results exhibit rather complex distributions of positive and negative entropy ΔS(T, B) and temperature ΔT(T, B) differences below and above T N when the direction of the magnetic field changes between directions c || B and c ⊥ B . The calculated results were confirmed by direct R-MCE measurements which, moreover, show an interesting angular dependence of R-MCE in the ordered phase, which seems to be related with the change of the effective magnetic field along the c axis during sample rotation. Thus, our study presents a new type of magnetic refrigerant with a rather large R-MCE for low temperature magnetic refrigeration, and points to further interesting magnetic features in the ordered phase of this frustrated system.