Synthesis and characterization of the new two-dimensional Heisenberg antiferromagnet double perovskite BaLaCuSbO6

摘要

The BaLaCuSbO6 double perovskite has been successfully synthesized by solid state reaction under an air atmosphere. Its structure was refined using powder neutron diffraction in the monoclinic space group I2/m with a 4% antisite disorder on the B cations. Magnetic measurements give signs of 2D-antiferromagnetic behaviour with T-N around 64 K. The Jahn-Teller distortion produced by Cu2+ ions favours a crystallographic tetragonal distortion and consequently the in-plane super-superexchange antiferromagnetic interactions, J(90 degrees), are favoured over the in-plane J(180 degrees) antiferromagnetic exchange interactions. Both, J and J' magnetic interactions have been evaluated according to a Heisenberg antiferromagnetic rectangular model using an approximation to Curie's law in powers of J/T, being vertical bar J vertical bar around 10 times stronger than vertical bar J'vertical bar.