%0 Journal Article
%A Fu, Zhendong
%A Xiao, Yinguo
%A Su, Yixi
%A Zheng, Yanzhen
%A Kögerler, Paul
%A Brückel, Thomas
%T Low-lying magnetic excitations and magnetocaloric effect of molecular magnet K $_{6}$ [V $_{15}$ As $_{6}$ O $_{42}$ (H $_{2}$ O)] · 8H $_{2}$ O
%J epl
%V 112
%N 2
%@ 0295-5075
%C Les-Ulis
%I EDP Science65224
%M FZJ-2015-07122
%P 27003
%D 2015
%X Low-temperature heat capacity measurements were performed on the molecular nanomagnet $\text{K}_{6}[\text{V}_{15}\text{As}_{6}\text{O}_{42}(\text{H}_{2}\text{O})] \cdot8\text{H}_{2}{\text{O}}$ (V15). The low-lying magnetic excitations are clearly evidenced by the Schottky anomalies in the specific-heat data. The energy levels determined from the low-temperature observables agree well with the three-spin model for V15. The magnetocaloric effect of V15 is examined. The maximum entropy change of $5.31\ \text{Jkg}^{-1}\text{K}^{-1}$ is found for a field change of $\Delta H =(8-0.5)\ \text{T}$ at ${\sim}1.5\ \text{K}$ . In spite of the low ground-state spin of V15, a drastic entropy change of $4.12\ \text{Jkg}^{-1}\text{K}^{-1}$ is observed for a field change of $\Delta H = (8-0.05)\ \text{T}$ at 0.4 K, which is comparable to the entropy change of some high-spin sub-kelvin magnetic coolers at such low temperatures. Anisotropy and consequent zero-field splitting result in this characteristic of V15 and may open new possibilities in the design of ultra-low-temperature molecular coolers.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000365323000023
%R 10.1209/0295-5075/112/27003
%U https://juser.fz-juelich.de/record/278947