Chiral and helical phase transitions in quasi-1D molecular magnets

We review recent experimental data obtained with quasi-one-dimensional (1D) molecular magnets Gd(hfac)3NITR. For Gd(hfac)3NITiPr the results can be coherently explained only in terms of the Villain’s conjecture: a chiral order at intermediate temperatures and helical order at low temperatures. In the case of weakly frustrated molecular magnetic chain compounds Gd(hfac)3NITPh, new specific heat measurements show the presence of a phase transition to the three-dimensional (3D) helical order, observed at T ∼ 0.63 K. In the temperature range 25–250 mK the experimental specific heat data are reproduced very well by a simple spin wave theory.

Graphical abstractWe review recent experimental and theoretical data obtained on quasi-one-dimensional molecular magnets Gd(hfac)3NITR. For Gd(hfac)3NITiPr is proposed a chiral order at intermediate temperature and an helical order at lower temperature, while for the compounds Gd(hfac)3NITPh specific heat measurements show the presence of the only three-dimensional (helical order) transition one.Figure optionsDownload full-size imageDownload as PowerPoint slide