The Magnetocaloric Effect in {[Cu(bapa)]3[Cr(CN)6]2}n·6nH2O at Low Temperatures

K. Ráczováa, M. Vavrab, M. Hegedüsb and E. Čižmára aInstitute of Physics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, SK-041 54 Košice, Slovakia bInstitute of Chemistry, Faculty of Science, P.J. Šafárik University, Moyzesova 11, SK-041 54 Košice, Slovakia

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The crystals of {[Cu(bapa)]3[Cr(CN)6]2}n·6nH2O (bapa = bis(3-aminopropyl)amine) are formed by infinite Cu(II)-Cr(III) antiparallel chains, which are connected into the third direction by additive [Cu(bapa)] moieties. The onset of long-range magnetic order at 3.2 K was observed by AC susceptibility. The study of the magnetocaloric effect from magnetization measurements yields a large entropy change -ΔSM=13.65 J K-1mol-1 (-ΔSM=12.25 J kg-1K-1) at the field change from 0 T to 3 T at temperature 4 K. The analysis of the critical behavior of -ΔSM suggests the value of critical exponent n = 0.577 at the ordering temperature characteristic for three-dimensional magnets with Ising anisotropy.

DOI: 10.12693/APhysPolA.133.429 PACS numbers: 75.30.Sg, 75.30.Gw, 75.10.Pq