Stable Tsai-type quinary 1/1 and 2/1 approximant crystals (ACs) with chemical compositions Au56.25Al10Cu7In13Tb13.75 and Au55.5Al10Cu7In13Tb14.5, respectively, exhibiting ferromagnetic (FM) long-range orders were successfully synthesized and studied for their magnetic properties and magnetocaloric effect. The 1/1 and 2/1 ACs primarily differ in their long-range atomic arrangement and rare earth (RE) distribution, with the latter approaching quasiperiodic order while still preserving periodicity. Analyses based on the scaling principle and Kouvel-Fisher (KF) relations suggested mean-field-like behavior near Curie temperatures in both compounds. From magnetization measurements and the Maxwell equation, a magnetic entropy change of -4.3 and -4.1 J/K mol Tb were derived under a magnetic field change of 7 T for the 1/1 and 2/1 ACs, respectively. The results indicated a prominent role of intra-cluster magnetic interactions on critical behavior and magnetic entropy of the Tsai-type compounds.
@article{arxiv.2310.14292,
title = {Critical behavior and magnetocaloric effect in Tsai-type 2/1 and 1/1 quasicrystal approximants},
author = {Farid Labib and Takafumi D. Yamamoto and Asuka Ishikawa and Ryuji Tamura},
journal= {arXiv preprint arXiv:2310.14292},
year = {2023}
}