Rotating magnetocaloric effect in highly anisotropic TbIII and DyIII single molecular magnets

• Published in: Scientific reports 2022-10, Vol.12 (1), p.16601-16601, Article 16601
• Main Authors: Konieczny, Piotr, Czernia, Dominik, Kajiwara, Takashi
• Format: Article
• Language: English
• Subjects: 639/301/119/2793; 639/301/119/997; 639/638/298/920; 639/766/119/997; Anisotropy; Cooling; Crystals; Entropy; Expected values; Humanities and Social Sciences; Ligands; Magnetic fields; Magnetism; multidisciplinary; Science; Science (multidisciplinary); Single crystals; Zinc
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-20893-2

The magnetocaloric effect (MCE) was investigated in highly anisotropic single crystals of two single molecule magnets (SMMs): [Ln III (Zn II L) 2 ]CF 3 SO 3 , where Ln = Tb, Dy and L = tripodal hexadentate Schiff base ligand. The structure of these paramagnetic compounds consists of identically oriented linear trinuclear clusters in a trigonal system with an easy direction c ∥Zn–Ln–Zn array and a hard plane ab ⊥Zn–Ln–Zn array. The magnitude of MCE measured for c ∥ H was significantly greater than MCE for ab ∥ H at a wide temperature range regardless of the studied SMM. Therefore, the rotating magnetocaloric effect (RMCE) was evaluated. The maxima of the magnetic entropy change for RMCE were obtained at 2.0 K and moderate fields: 3.9 J K −1 kg −1 at µ 0 H  = 1.3 T for Ln = Tb and 3.3 J K −1 kg −1 at µ 0 H  = 1.1 T for Ln = Dy. The relative efficiency of RMCE compared to the MCE measured in c ∥ H was as high as 99% at low magnetic fields.