Change of magnetic short range order at metal-insulator phase transition

The wavenumber dependent susceptibility in V ₅O ₉ shows that the jump of susceptibility at the metal-insulator transition is not due to antiferromagnetic correlations expected in a Mott insulator but to the onset of ferromagnetic correlations in the metallic phase with a small, intinerant type V moment of 0.6μ _B in both phases.