Magnetic susceptibility of Alq3 powder, pure and Al-doped 8-hydroxyquinoline

Single-crystal nanowires several microns long and 100–200 nm in diameter were grown by physical vapour deposition from mixed Alq3/γ-Al2O3 powder. The crystals are orthorhombic Al-doped 8-hydroxyquinoline. The molar susceptibility is −3×10−9 at room temperature, and it shows a Curie-law upturn below about 50 K. The approach to saturation at low temperature indicates a density of S=12 defects 4×10−4 per formula unit. Pure 8-hydroxyquinoline and aluminium (Alq3) behave similarly. Pressed pellets exhibit much increased paramagnetic susceptibility due to iron ions scavanged from the steel die. Subsequent melting of these samples produces a ferromagnetic signal of order 0.01 A m2 kg−1, which is attributed to metallic iron nanoclusters in the organic material.