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

TL;DR

This paper investigates the magnetization process of an anisotropic spin-1 Heisenberg dimer, revealing how single-ion anisotropy influences the emergence and breakdown of an intermediate magnetization plateau, supported by theoretical and experimental comparisons.

Contribution

It provides a detailed theoretical analysis of the magnetization process considering anisotropy effects, aligning with recent experimental high-field measurements.

Findings

Intermediate magnetization plateau depends on single-ion anisotropy and field orientation.

Breakdown of the plateau is linked to anisotropy strength.

Magnetization process shows spatial dependence on applied magnetic field.

Abstract

The magnetization process of the spin-1 Heisenberg dimer model with axial and rhombic single-ion anisotropy terms is particularly investigated in connection with recent experimental high-field measurements performed on the single-crystal sample of the homodinuclear nickel(II) compound [Ni2(Medpt)2(ox)(H2O)2](ClO4)2.2H2O (Medpt=methyl-bis(3-aminopropyl)amine). The results obtained from the exact numerical diagonalization reveal a striking magnetization process with a marked spatial dependence on the applied magnetic field for arbitrary but non-zero 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 single-ion anisotropy terms 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.