Two Ln(III)2 (Ln = Gd and Dy) compounds showing magnetic refrigeration and slow magnetic relaxation

Abstract Two new Ln2 compounds, namely [Ln2(L)2(CH3OH)2] (Ln = Gd (1) and Dy (2)), have been successfully synthesized and further characterized by crystallography. Structural analysis shows that both 1 and 2 are binuclear compounds, and each LnIII ion is eight-coordinated model and the coordination polyhedron of centre LnIII ion can be represented as a distorted dodecahedron with triangular faces. The magnetic studies reveal that weak antiferromagnetic exchange is existed between the two neighbouring Gd(III) ions in 1. Furthermore, for 1, it exhibits magnetic refrigeration property (magnetic entropy changes −ΔSm = 24.75 J kg−1 K−1 for magnetic field intensity ΔH = 7.0 T at 3.0 K); while for 2, it displays slow magnetic relaxation behavior under zero dc field. When under an external dc field (dc = 3000 Oe), remarkable single-molecule-magnet (SMM) behavior was observed in 2 with the anisotropic barrier (ΔE/kB) of 16.65 K and pre-exponential factor (τ0) of 3.12 × 10−6 s.