Observation of the influence of dipolar and spin frustration effects on the magnetocaloric properties of a trigonal prismatic {Gd-7} molecular nanomagnet

Pineda EM, Lorusso G, Zangana KH, et al. Observation of the influence of dipolar and spin frustration effects on the magnetocaloric properties of a trigonal prismatic {Gd-7} molecular nanomagnet. CHEMICAL SCIENCE. 2016;7(8):4891-4895.We report the synthesis and structure of a molecular {Gd-7} cage of the formula ((Pr2NH2)-Pr-i)(6)[Gd-7(mu(3)-OH)(3)(CO3)(6)((O2CBu)-Bu-t)(12)] which has crystallographic C-3h symmetry. Low temperature specific heat and adiabatic demagnetization experiments (the latter achieving temperatures below 100 mK), lead to the observation of the effects of both intramolecular dipolar interactions and geometric spin frustration. The dipolar interaction leads to a massive rearrangement of energy levels such that specific heat and entropy below 2 K are strongly modified while magnetic susceptibility and magnetization above 2 K are not affected. The consequences of these phenomena for low temperature magnetocaloric applications are discussed

Observation of the Influence of Dipolar and Spin Frustration Effects on the Magnetocaloric Properties of a Trigonal Prismatic {Gd7} Molecular Nanomagnet

We report the synthesis and structure of a molecular {Gd7} cage of the formula (iPr2NH2)6[Gd7(μ3-OH)3(CO3)6(O2CtBu)12] which has crystallographic C3h symmetry. Low temperature specific heat and adiabatic demagnetization experiments (the latter achieving temperatures below 100 mK), lead to the observation of the effects of both intramolecular dipolar interactions and geometric spin frustration. The dipolar interaction leads to a massive rearrangement of energy levels such that specific heat and entropy below 2 K are strongly modified while magnetic susceptibility and magnetization above 2 K are not affected. The consequences of these phenomena for low temperature magnetocaloric applications are discussed.EMP thanks the Panamanian agency SENACYT-IFARHU. KZ thanks the KRG-Scholarship program in “Human Capacity Development (HCDP)”. JS thanks the Deutsche Forschungsgemeinschaft (DFG SCHN 615/20-1) for continuous support. Supercomputing time at the LRZ Garching is gratefully acknowledged. GL and ME thank Spanish MINECO (MAT2015-68204-R). We also thank EPSRC (UK) for funding an X-ray diffractometer (grant number EP/K039547/1).Peer Reviewe