EPR and magnetization studies on single crystals of a heterometallic (Cu^{II}} and Cr^{III}) complex: zero-field splitting determination

TL;DR

This study investigates the magnetic properties of a heterometallic complex using EPR and magnetization measurements, successfully determining the zero-field splitting parameter D and confirming its extraction from macroscopic magnetization data.

Contribution

The paper demonstrates that the zero-field splitting parameter D of Cr(III) can be accurately obtained from magnetization measurements, complementing EPR spectroscopy in a heterometallic complex.

Findings

Magnetic anisotropy observed at low temperatures.

Zero-field splitting parameter D calculated from magnetization data.

Confirmation that D can be derived from macroscopic measurements.

Abstract

Magnetic properties of single crystals of the heterometallic complex [Cu(bpy)$_3$]$_2$[Cr(C$_2$O$_4$)$_3$]NO$_3\cdot $9H$_2$O (bpy = 2,2'-bipyridine) have been investigated. From the recorded EPR spectra, the spin-Hamiltonian parameters have been determined. The magnetization measurements have shown magnetic anisotropy at low temperatures, which has been analysed as a result of the zero-field splitting of the Cr$^{\mathrm{III}}$ ion. By fitting the exactly derived magnetization expression to the measured magnetization data, the axial zero-field splitting parameter, D, has been calculated. Comparing to the EPR measurements, it has been confirmed that $D$ can be determined from the measurements of the macroscopic magnetization on the single crystals.