| Issue |
EPL
Volume 112, Number 2, October 2015
|
|
|---|---|---|
| Article Number | 27003 | |
| Number of page(s) | 6 | |
| Section | Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties | |
| DOI | https://doi.org/10.1209/0295-5075/112/27003 | |
| Published online | 29 October 2015 | |
Low-lying magnetic excitations and magnetocaloric effect of molecular magnet K6[V15As6O42(H2O)] · 8H2O
1 Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ - Lichtenbergstraße 1, D-85747 Garching b. München, Germany
2 Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, Forschungszentrum Jülich GmbH - D-52425 Jülich, Germany
3 Center for Applied Chemical Research, Frontier Institute of Science and Technology, Xi'an Jiaotong University 710049 Xi'an, China
4 Institut für Anorganische Chemie, RWTH Aachen University - D-52074 Aachen, Germany
Received: 1 June 2015
Accepted: 10 October 2015
Low-temperature heat capacity measurements were performed on the molecular nanomagnet ![$\text{K}_{6}[\text{V}_{15}\text{As}_{6}\text{O}_{42}(\text{H}_{2}\text{O})] \cdot8\text{H}_{2}{\text{O}}$](/articles/epl/abs/2015/20/epl17442/epl17442_tex_eq1.png)
(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 
is found for a field change of 
at 
. In spite of the low ground-state spin of V15, a drastic entropy change of 
is observed for a field change of 
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.
PACS: 75.40.Cx – Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.) / 75.30.Sg – Magnetocaloric effect, magnetic cooling / 75.50.Xx – Molecular magnets
© EPLA, 2015
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