Breakdown of an intermediate plateau in the magnetization process of anisotropic spin-1 Heisenberg dimer: Theory vs. experiment

• Published in: Physica. B, Condensed matter Vol. 403; no. 18; pp. 3146 - 3153
• Main Authors: Strečka, J., Hagiwara, M., Baláž, P., Jaščur, M., Narumi, Y., Kimura, S., Kuchár, J., Kindo, K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2008; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Domain effects, magnetization curves, and hysteresis; Exact diagonalization; Exact sciences and technology; Heisenberg dimer; Magnetic properties and materials; Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects; Magnetization plateau; Molecular magnets; Physics; Studies of specific magnetic materials; 75.10.Jm; 05.50.+q; 75.45.+j; Magnetization plateau; Heisenberg dimer; 75.30.Gw; Exact diagonalization; Diagonalization; Magnetization; Molecular magnet; Magnetic field effects; Heisenberg model; Chlorates; Nickel complexes; Monocrystals; Magnetic anisotropy; High field; Saturation magnetization
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2008.03.025

The magnetization process of the spin-1 Heisenberg dimer model with the uniaxial or biaxial single-ion anisotropy is particularly investigated in connection with recent experimental high-field measurements performed on the single-crystal sample of the homodinuclear nickel(II) compound [ Ni 2 ( Medpt ) 2 ( μ - ox ) ( H 2 O ) 2 ] ( ClO 4 ) 2 · 2 H 2 O (Medpt=methyl-bis(3-aminopropyl)amine). The results obtained from the exact numerical diagonalization indicate a striking magnetization process with a marked spatial dependence on the applied magnetic field for arbitrary but finite single-ion anisotropy. It is demonstrated that the field range, which corresponds to an intermediate magnetization plateau emerging at a half of the saturation magnetization, basically depends on a single-ion anisotropy strength as well as a spatial orientation of the applied field. The breakdown of the intermediate magnetization plateau is discussed at length in relation to the single-ion anisotropy strength.