Ferrimagnetic ringMn6R6in megagauss fields

Abstract

The dependence of the magnetic susceptibility on the magnetic field is investigated for the ferrimagnetic ring $[\mathrm{Mn}(\mathrm{hfac}{)}_{2}\mathrm{NITPh}{]}_{6}.$ The spikes of the susceptibility detected in a magnetic field ranging from 90 T to 285 T are interpreted as a manifestation of magnetic quantum jumps under spin reorientation from ferrimagnetic to ferromagnetic structure. The characteristic feature of the molecular ferrimagnetic ring ${\mathrm{Mn}}_{6}{R}_{6}$ is a deficiency of pair Heisenberg exchange interactions for the description of its magnetic properties in high magnetic fields. The comparison of the experimental data with the results of theoretical calculations allows us to prove the existence of a strong three-spin interaction in this molecular cluster and to determine the values of exchange constants. Constant of the Heisenberg exchange interaction is $J=39.8{\mathrm{cm}}^{\ensuremath{-}1}$ and the constant of the three-spin interaction is ${J}_{3}/J=0.14.$ For the calculation of the ground-state spin structure, the modified Lanczos method has been used.