Exploring the Slow Relaxation of the Magnetization in CoIII-Decorated {DyIII 2} Units

Abstract

We have prepared and structurally characterized a new member of the butterfly-like {CoIII 2DyIII 2} single-molecule magnets (SMMs) through further CoIIIdecoration, with the formula [CoIII 4DyIII 2(OH)2(teaH)2(tea)2(Piv)6] (teaH3=triethanolamine; Piv=trimethylacetate or pivalate). Direct current (DC) susceptibility and magnetization measurements were performed allowing the extraction of possible crystal-field parameters. A simple electrostatic modeling shows reasonable agreement with experimental data. Alternating current (AC) susceptibility measurements under a zero DC field and under small applied fields were performed at different frequencies (i.e., 10–1500 Hz) and at low temperatures (i.e., 2–10 K). Multiple magnetization relaxation pathways are observed. Comparison with previously reported {CoIII 2DyIII 2} complex measurements allows an overall discussion about the origin of the dynamic behavior and its relationship with crystal-field split ground multiplet sublevels.