SMM Behaviour of the Butterfly {CrIII2DyIII2} Pivalate Complex and Magneto‐structurally Correlated Relaxation Thermal Barrier

• Published in: Chemistry : a European journal Vol. 28; no. 59; pp. e202201450 - n/a
• Main Authors: Mecchia Ortiz, Juan H., Cabrosi, Daiana, Carrella, Luca M., Rentschler, Eva, Alborés, Pablo
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 21.10.2022
• Subjects: Chemistry; Chromium; Coercivity; Correlation; Dysprosium; Ferromagnetism; Gadolinium; heteronuclear 3d/4 f; Hysteresis; Magnetic properties; Magnetization; magneto structural correlation; Magnetometers; Quantum tunnelling; SMM; Structural analysis; Thermal barriers; Trivalent chromium; tunneling suppression
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202201450

We are reporting the synthesis, single‐crystal X‐ray structure characterization, and magnetic property investigations of the pivalate butterfly {CrIII2LnIII2} 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 {CrIII2DyIII2} complexes, reveals the existence of a magneto‐structural correlation between Ueff, 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. We report a new pivalate butterfly {CrIII2LnIII2} system with magnetization tunneling relaxation suppresion and hysteresis opening up to 3.6 K in the Ln=Dy complex, due to Cr−Dy exchange interaction. We have found a magneto‐structural correlation between the Orbach thermal barrier for magentization reversal and the mean Cr−Dy bond lenght across all literature reported butterfly {CrIII2DyIII2} complexes.