Controlled crystallization of Mn12 single-molecule magnets by compressed CO2 and its influence on the magnetization relaxation

6 pages, 6 figures, 2 tables.Micro- and sub-micro particles of complex [Mn12O12(O2CC6H5)16(H2O)4] ( 1) with controlled size and polymorphism have been prepared by dense-gas crystallization techniques, showing a remarkable particle size influence on the magnetization relaxation rates.This work was supported by DGI (Spain) under projects MAT2002-0043 and MAT2003-04699 and by the European Commission under the NoE MAGMANET (Contract NMP3- CT-2005-515767) and QUEMOLNA Marie Curie RTN (Contract MRTN-CT-2003-5044880). Javier Campo and Nora Ventosa thank the Ramon y Cajal Program of Ministerio de Educación y Tecnología (Spain) for their contracts. Maria Muntó thanks the Consejo Superior de Investigaciones Científicas (CSIC) for her PhD bursary and Jordi Gómez- Segura thanks the European Community for his PhD grant.Peer reviewe

Low-Temperature Heat Capacity Anomalies in Ordered and Disordered Phases of Normal and Deuterated Thiophene

We measured the specific heat Cp of normal (C4H4S) and deuterated (C4D4S) thiophene in the temperature interval of 1 = T, K = 25. C4H4S exhibits a metastable phase II2 and a stable phase V, both with frozen orientational disorder (OD), whereas C4D4S exhibits a metastable phase II2, which is analogous to the OD phase II2 of C4H4S and a fully ordered stable phase V. Our measurements demonstrate the existence of a large bump in the heat capacity of both stable and metastable C4D4S and C4H4S phases at temperatures of ~10 K, which significantly departs from the expected Debye temperature behavior of Cp ˜ T3. This case study demonstrates that the identified low-temperature Cp anomaly, typically referred to as a “Boson-peak” in the context of glassy crystals, is not exclusive of disordered materials.Peer ReviewedPostprint (published version

Studies on the magnetic ground state of a spin Möbius strip

Here we report the synthesis, structure and detailed characterisation of three n-membered oxovanadium rings, Nan[(V=O)nNan(H2O)n(α, β, or γ-CD)2]⋅mH2O (n = 6, 7, or 8), prepared by the reactions of (V=O)SO4⋅xH2O with α, β, or γ-cyclodextrins(CDs) and NaOH in water. Their alternating heterometallic vanadium/sodium cyclic core structures were sandwiched between two CD moieties such that O-Na-O groups separated neighbouring vanadyl ions. Antiferromagnetic interactions between the S = ½ vanadyl ions led to S = 0 ground states for the even-membered rings, but to two quasi-degenerate S = ½ states for the spin-frustrated heptanuclear cluster

Multi-layered flyer accelerated by laser induced shock waves

Copyright 2000 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 7(2), 676-680, 2000 and may be found at http://dx.doi.org/10.1063/1.87385