Attenuated Oscillation of the Tunneling Magnetoresistance in a Ferromagnet-Metal-Insulator-Ferromagnet Tunneling Junction

The tunneling magnetoresistance (TMR) ratio is investigated in a ferromagnet-metal-insulator-ferromagnet planar tunneling junction by use of the spin-polarized free-electron model. Due to the coherence multiple reflective scatterings within the metallic layer, the TMR ratio oscillates as the metallic thickness increases. Due to the same scatterings, not only electrons with the out-of-plane energy E _xi close to the Fermi energy EF but also electrons with E _xi below EF can tunnel sufficiently through the tunneling junction, which leads to the attenuated oscillation of the TMR ratio.