Two-Step Magnetic Ordering in Quasi-One-Dimensional Helimagnets: Possible Experimental Validation of Villain’s Conjecture about a Chiral Spin Liquid Phase

Low-temperature specific heat, magnetic susceptibility, and zero-field muon spin resonance (SR)measurements have been performed in the quasi-one-dimensional molecular helimagnetic compoundGdhfac3NITEt. The specific heat presents two anomalies at T02:190:02K and TN 1:880:02K,which both disappear upon the application of a weak magnetic field. Conversely, magnetic susceptibilityand SR data show the divergence of two-spin correlation functions only at TN 1:88 0:02 K. Theseresults suggest an experimental validation of Villain’s conjecture of a two-step magnetic ordering in quasione-dimensional XY helimagnets; i.e., the paramagnetic phase and the helical spin solid phase areseparated by a chiral spin liquid phase, where translational invariance is broken without violation ofrotational invariance.