Patent ID: 7940042

Claim:
A method for testing a magnetoresistive effect element, comprising the steps of: obtaining a ferromagnetic resonance frequency f 0 of said magnetoresistive effect element to be tested by applying an external magnetic field in a track-width direction to said magnetoresistive effect element; calculating a stiffness magnetic field H stiff from the obtained ferromagnetic resonance frequency f 0 using a predetermined formula; obtaining a relationship of a stiffness magnetic field H stiff with respect to an external magnetic field applied in the track-width direction from the applied external magnetic field and the calculated stiffness magnetic field H stiff ; obtaining a uniaxial anisotropic magnetic field H k of a free layer of said magnetoresistive effect element from the obtained relationship of the stiffness magnetic field H stiff with respect to the external magnetic field applied; and judging whether said magnetoresistive effect element is good product or not by comparing the obtained uniaxial anisotropic magnetic field H k with a predetermined threshold.