Hysteresis In A Bimetallic Holmium Complex: A Synergy Between Electronic And Nuclear Magnetic Interactions

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 Delta(A) = 0.8 and Delta(B) = 10 cm(-1) and that there is a small ferromagnetic coupling of J = 1 cm(-1) ((H) over cap (S) = -JS(A) . 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.