Calculation of Resistivity of the Insulating Layer in Tunnelling-Magnetoresistive Head by Fast Green Function Method

We calculate the resistivity of the insulating layer in a tunnelling-magnetoresistive (TMR) magnetic head by using the Landauer--Büttiker formula with a fast Green function method, where a recursive process with a faster simulation speed and higher accuracy is carried out to substitute the inversion of Green’s matrix. A tight-binding model with an energy barrier ΔE is utilized to simulate the magnetoresistive tunnelling junction in the TMR head. The resistivity of the insulating layer is 2.6×10⁵μΩcm with two oxygen-ion layers and ΔE=2.5eV, which agrees with the experimental data.