Local current distribution and electrical properties of a magnetic tunnel junction using conducting atomic force microscopy

Local topographical and electrical properties were simultaneously measured for a magnetic tunnel junction formed by Ta (50 Å)/Ni-Fe (20 Å)/Cu (50 Å)/Mn₇₅ Ir₂₅ (100 Å)/Co₇₀Fe₃₀(40 Å)/Al-O (8-15 Å)/Co₇₀Fe₃₀ (40 Å)/Ni-Fe (100 Å)/Ta (50 Å). Local current-voltage (I-V) characteristic curves were obtained for different contrast levels in the electrical current distribution images on the test sample. With the purpose of obtaining quantitative values for the barrier characteristics, data was analyzed by the Simmons´ equation from -1.0 to 1.0 V. The magnetoresistance ratio values were estimated to be 35.02%, with a bias voltage of 0.36 V, when applying a magnetic field of ±200 Oe. In addition, a study on the ramping effect on the dielectric tunneling capacitance and analytical resistance-capacitance (RC) model were carried out.