SMM Behaviour of the Butterfly {Cr<sup>III</sup><sub>2</sub>Dy<sup>III</sup><sub>2</sub>} Pivalate Complex and Magneto‐structurally Correlated Relaxation Thermal Barrier
Juan H. Mecchia Ortiz, Daiana Cabrosi, Luca M. Carrella, Eva Rentschler, Pablo Alborés
Abstract
Abstract We are reporting the synthesis, single‐crystal X‐ray structure characterization, and magnetic property investigations of the pivalate butterfly {Cr III 2 Ln III 2 } complexes with Ln= Gd and Dy and the isostructural Y(III) sample. We found an anti‐ferromagnetic Cr(III)‐Ln(III) exchange interaction, which, as previously observed in related Cr(III)/Ln(III) systems, plays a key role in suppressing quantum tunnelling of magnetization and enhances the SMM performance in the Dy(III) complex. In fact, a pure Orbach relaxation mechanism, with absence of QT regime, is observed with a thermal barrier of 50 cm −1 , leading to magnetization hysteresis opening, measured with a commercial magnetometer, up to 3.6 K with a coercive field of 2.9 T. Analysis of SMM behaviour in literature‐known butterfly {Cr III 2 Dy III 2 } complexes, reveals the existence of a magneto‐structural correlation between U eff , the thermal barrier size, and the mean Cr−Dy bond distances. Moreover, a clear correlation is found for the thermal barrier magnitude and the maximum temperature hysteresis opening and coercive field.