Slow Spin Dynamics between Ferromagnetic Chains in a Pure-Inorganic Framework

The crystal structure of the new phase BaCoII2(AsIII3O6)2·2­(H2O) is built from the stacking of infinite [BaCo2(As3O6)2·H2O] sheets containing ∞[CoIIO4]6– chains interconnected by perpendicular ∞[AsIIIO2]− chains. It shows a metamagnetic transition below ∼9 K at a critical field of ∼0.11 T, leading to a moment value of 70% of the expected saturation, related to the spin flip between individual robust canted ferromagnetic chains. We propose a field-dependent scenario with magnetic moments lying in the CoIIO6 octahedral basal planes, fully compatible with our experimental results. Magnetic measurements under ac-field show slow spin dynamics with an intrinsic single-chain magnet (SCM)-like component slightly modified in the field-aligned regime. The characteristic relaxation time and energy barrier are about τo = 5.1 × 10–10 s and Δτ = 35.3 K at Hdc = 0, respectively, which falls close to values found for other (but organometallic) SCM CoII chains. This magnetic behavior is unique in the field of pure-inorganic compounds.