2006/12/13 by T. Lancaster, Tom Lancaster, Stephen J. Blundell +26 · 3 citations
Chemistry · Materials Science · Physics and Astronomy · #Antiferromagnetism #Chemistry #Condensed matter physics #Crystallography #Heat capacity #Magnetism in coordination complexes #Muon spin spectroscopy #Order (exchange) #Organic and Molecular Conductors Research #Physics #Physics of Superconductivity and Magnetism #Specific heat #Superconductivity #Thermodynamics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.75.094421
published as Phys. Rev. B 75, 094421 (2007) · 7 pages, 4 figures
arxiv created 2006/12/13 · openalex publication_date 2007/03/21 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present an investigation of magnetic ordering in the two-dimensional S=1∕2 quantum magnet Cu(Pz)2(ClO4)2 using specific heat and zero-field muon-spin relaxation (\ensuremathμ+SR). The magnetic contribution to the specific heat is consistent with an exchange strength of 17.7(3)\phantom\rule0.3em0exK. We find unambiguous evidence for a transition to a state of three-dimensional long-range order below a critical temperature TN=4.21(1)\phantom\rule0.3em0exK using \ensuremathμ+SR even though there is no feature in the specific heat at that temperature. The absence of a specific heat anomaly at TN is consistent with recent theoretical predictions. The ratio of TN∕J=0.24 corresponds to a ratio of intralayer to interlayer exchange constants of \ensuremath|J^\ensuremath'∕J\ensuremath|=6.8\ifmmode×\else\texttimes\fi10^\ensuremath-4, indicative of excellent two-dimensional isolation. The scaled magnetic specific heat of [Cu(Pz)2(HF2)]BF4, a compound with an analogous structure, is very similar to that of Cu(Pz)2(ClO4)2 although both differ slightly from the predicted value for an ideal 2D S=1∕2 Heisenberg antiferromagnet.