Vanadium octacyanoniobate-based magnet with a Curie temperature of 138 K.

In this work, we prepared a three-dimensional vanadium octacyanoniobate-based magnet, K(0.10)V(II)(0.54)V(III)(1.24)[Nb(IV)(CN)(8)].(SO(4))(0.45).6.8H(2)O. This compound exhibits ferrimagnetism with a Curie temperature of 138 K, in which the sublattice magnetizations of V(II) (S = (3)/(2)) and V(III) (S = 1) are antiparallelly ordered to that of Nb(IV) (S = (1)/(2)). The estimated superexchange interaction constants of V(II)-Nb(IV) and V(III)-Nb(IV) are -51 and -25 cm(-1), respectively.