Magnetic order in the quasi-one-dimensional spin-1∕2molecular chain compound copper pyrazine dinitrate

Abstract

We present evidence of magnetic order in the quasi-one-dimensional spin-1/2 molecular chain compound, copper pyrazine dinitrate $\mathrm{Cu}({\mathrm{C}}_{4}{\mathrm{H}}_{4}{\mathrm{N}}_{2}){(\mathrm{N}{\mathrm{O}}_{3})}_{2}$. Zero field muon-spin relaxation measurements made at dilution refrigerator temperatures show oscillations in the measured asymmetry characteristic of a quasistatic magnetic field at the muon sites. Our measurements provide convincing evidence for long-range magnetic order below a temperature ${T}_{\mathrm{N}}=107(1)\phantom{\rule{0.3em}{0ex}}\mathrm{mK}$. This leads to an estimate of the interchain coupling constant of $\ensuremath{\mid}{J}^{\ensuremath{'}}\ensuremath{\mid}∕{k}_{\mathrm{B}}=0.046\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and to a ratio of $\ensuremath{\mid}{J}^{\ensuremath{'}}∕J\ensuremath{\mid}=4.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$.