Magnetic properties of copper dimolybdate CuMo sub(2)O sub(7) times 3H sub(2)O

Magnetic properties of copper dimolybdate trihydrate CuMo sub(2)O sub(7) times 3H sub(2)O have been studied from room temperature down to 2 K with the use of ac and dc magnetometry. There was no sign of long range order: however, the compound deviates from the classical Curie law for paramagnetic systems. This situation is due to exchange interactions between Cu ions forming dimers, whereas Mo ions do not possess magnetic moments. The estimated value of J sub(ex) is -2.74(1) K from fitting the dc susceptibility and -3.01(1) K from the fit of magnetization versus magnetic field. The antiferromagnetic coupling is confirmed by the value of [theta]= -4.0(3) K from the Curie-Weiss analysis. The dynamic properties measured by ac susceptibility as a function of applied dc field indicate three regions of different magnetic relaxation behaviors.