Tunnel magnetoresistance of π-cyclopentadienyl complexes of the main group elements

Abstract

Spin current in π-cyclopentadienyl (Cp) complexes of the main group elements have been studied by the first-principles method of density functional theory. The characteristics of spin current were examined by using a model of Cp-metal complex, sandwiched between ferromagnetic electrodes. Spin currents were varied by changing the main group element. The Cp complex of the p-block main group elements showed a tunnel magnetoresistance (TMR) effect at a low bias voltage, while that of the s-block main group elements did not show this effect. This is because the spin-filtering effect under a parallel alignment of ferromagnetic electrodes is deeply linked to the TMR effect. The bonding state between the Cp ring and the metal atom, whether covalent or ionic bond, was the important factor responsible for the TMR effect.