CO(OH)(NO3)BULLET-H2O - A NOVEL DOUBLE-CHAIN COMPOUND WITH COMPETING INTERACTIONS

Magnetic susceptibility and magnetization measurements of the newly synthesized cobalt(II) hydroxide nitrate Co(OH)(NO3).H2O show that this system presents above 2.5 K a low-dimensional magnetic behavior. It is described in terms of Ising-like S = 1/2 double chains with two nearest-neighbor exchange interactions, J1 = 22.8 K and J2 = -9.75 K. The couplings between cobalt(II) ions are discussed using structural data for the in-chain and interchain exchange pathways. A weak coupling between double chains (J' almost-equal-to 0.2 K) leads to an antiferromagnetic ordering below 2.5 K which undergoes a metamagnetic transition in relatively low magnetic field.