High Field Magnetization of Cr-Dimer Complexes

Abstract

High field magnetizations of three Cr-dimer complex powders, [Cr₂(acac)₄(4-X-phO)₂] (X=H, Cl, CH₃), are investigated up to 60 T at 1.3 K, and successive multistep metamagnetizations are found. They are explained by the model that two Cr³⁺ ions with spin S of 3/2 form an antiferromagnetic dimer with the singlet ground state and that the successive crossovers with the excited S=1, 2 and 3 states occur under increasing magnetic field. Biquadratic exchange interaction should also be taken into account. Additional fine structures are observed and attributed to two kinds of dimers. Main exchange parameters of μ-Cl-, H- and CH₃-phO complexes are determined as −12.0 K, −11.4 K and −14.7 K, respectively. These values are in good agreement with the magnetic susceptibility data.