Low-temperature specific heat $C\left(T\right)\mathrm{}$ and zero-field muon spin resonance $\left({\mu }^{+}\mathrm{SR}\right)$ measurements were performed in ${\mathrm{Gd}\left(\mathrm{hfac}\right)\mathrm{}}_3\mathrm{NITiPr},$ a quasi-one-dimensional molecular magnet with competing nearest-neighbor and next-nearest-neighbor intrachain exchange interactions. The specific heat data exhibit a $\lambda$ peak at $T_0=2.08\mathrm{}\pm 0.01\mathrm{K}$ that disappears upon the application of a 5 T magnetic field. Conversely, the ${\mu }^{+}\mathrm{SR}$ data do not present any anomaly at $T\approx 2$ K, proving the lack of divergence of the two-spin correlation function as required for usual three-dimensional long-range helical order. Moreover, no muon spin precession can be evinced from the ${\mu }^{+}\mathrm{SR}$ asimmetry curves, thus excluding the presence of a long-range-ordered magnetic lattice. These results provide indications for a low-$T$ phase where chiral order is established in absence of long-range helical order.

• Received 7 October 2002

DOI:https://doi.org/10.1103/PhysRevB.67.224408