Experimental validation of Villain's conjecture about magnetic ordering in quasi-1D helimagnets

Low-temperature magnetic susceptibility, zero-field muon spin resonance and specific heat measurements have been performed in the quasi-one-dimensional (1D) molecular helimagnetic compound Gd(hfac)3NITEt. The specific heat presents two anomalies at T0 = 2.19(2) K and TN = 1.88(2) K, while susceptibility and zero-field muon spin resonance show anomalies only at TN = 1.88(2) K. The results suggest an experimental validation of Villain's conjecture of a two-step magnetic ordering in quasi-1D XY helimagnets: the paramagnetic phase and the helical spin solid phases are separated by a chiral spin liquid, where translational invariance is broken without violation of rotational invariance.