RESUMO
A new triangular lattice compound Gd3Cu9(OH)19Br8 has been synthesized by the hydrothermal method. The structure, magnetism and magnetocaloric effect of Gd3Cu9(OH)19Br8 have been studied by X-ray diffraction, magnetic susceptibility, isothermal magnetization and specific heat measurements. In Gd3Cu9(OH)19Br8, the Cu2+ ions form a Kagome lattice along the ab plane, and Gd3+ ions are located in the center of hexagonal holes of the Kagome layer. The Cu-sublattice and Gd-sublattice overlap and constitute a magnetic triangular lattice. The temperature dependence of susceptibility and specific heat curves indicate no magnetic transition down to 2 K, suggesting a paramagnetic-like behavior at low temperature. The magnetocaloric effect (MCE) at low temperature has been calculated according to Maxwell's equations. The maximum value of magnetic entropy change -ΔS M is 26.04 J kg-1 K-1 and adiabatic temperature change ΔT ad is 13.79 K, for a field change of 0-7 T, indicating a potential application of this compound in the field of magnetic refrigeration at low temperature. The influence of 4f-3d interaction on magnetism and MCE is also discussed.
RESUMO
The mol-ecule of the title Schiff base compound, C(15)H(14)N(2)O(5), was obtained from a condensation reaction of 4-acet-oxy-3-meth-oxy-benzaldehyde and 2-furyl-carbonyl-hydrazide. In the mol-ecule, the furyl ring makes a dihedral angle of 14.63â (10)° with the benzene ring. In the crystal, inter-molecular N-Hâ¯O hydrogen bonds link the mol-ecules into chains along the b axis. Futhermore, weak C-Hâ¯O inter-actions connect the chains, forming corrugated layers parallel to (001). The dihedral angle between the rings is 14.63â (10)°.