We report a bimetallic holmium(III) complex showing a S-shaped magnetic hysteresis at low temperature. The complex is investigated by x-ray crystallography, magnetometry, single crystal microsquid measurements, and first-principles calculations. A model Hamiltonian including electronic and nuclear magnetic moments is used to fit all experimental data. We conclude that the Ho(III) may be described as non-Kramers doublets with respective gaps of ${\mathrm{\Delta }}_A=0.8$ and ${\mathrm{\Delta }}_B=10 {\mathrm{cm}}^{-1}$ and that there is a small ferromagnetic coupling of $J=1 {\mathrm{cm}}^{-1}$ (${\widehat{\mathcal{H}}}_S=-J{\mathit{S}}_A·{\mathit{S}}_B$). As in previous works, the hysteresis arise from the hyperfine structure of the Ho(III) ions. The S-shaped form of the hysteresis reflects the avoided crossing of the electronic states in the non-Kramers doublets.

• Received 21 July 2017
• Revised 20 October 2017

DOI:https://doi.org/10.1103/PhysRevB.96.214427