Data for Magnetic field induced ordering in the spin-1/2 chiral chain compound [Cu(pym)(H2O)4]SiF6·H2O

Previous measurements on this material have shown the absence of magnetic order down to surprisingly low temperatures ≥ 20 mK, as well as the presence of an energy gap for magnetic excitations that grows linearly with magnetic field.

Here we find evidence at dilution refrigerator temperatures for a field-induced transition to long-range magnetic order above an applied magnetic field of 3 T. From the polarization of magnetic moments observed with magnetic fields applied in the [−1, 2, 0] direction, we can identify the static magnetic structure that best accounts for the data. The proposed model is supported microscopically by the presence of an alternating component of the g tensor, which produces an internal two-fold staggered field that dictates both the direction of the ordered moments and the effective coupling between adjacent chains.