Effect of electron doping on the magnetic properties of spin-Peierls like material α′-NaV 2O 5

Abstract

Na 1+ x V 2O 5 ( x = 0.04 and 0.10) powder were synthesized by solid-state reaction under the condition of excess NaVO 3 with the protection of pure Nitrogen. Both of them showed a typical S = 1/2 one-dimensional (1D) antiferromagnetic Heisenberg linear chain behaviour at high temperature. At low temperature region, Na 1.04V 2O 5 displayed a spin-Peierls like transition at 35 K. The susceptibility of Na 1.10V 2O 5 increased with the decreasing of temperature, without spin-singlet transition. The increase of the susceptibility in Na 1.10V 2O 5 at low temperature results from the isolated V 4+ ions distributed in the nonmagnetic V 5+ chains due to the electron doping. The Curie–Weiss fitting between 4 K and 10 K indicated that the electron doping in α′-NaV 2O 5 induces the Curie term and thus results in the suppression and disappearance of the spin-singlet.