Second-harmonic magneto-optic Kerr effect from spin-valve test structures: correlation with magnetoresistance response

We have simultaneously measured the second-harmonic magneto-optic Kerr effect and the magnetoresistance of patterned Ta/Ni/sub 81/Fe/sub 19//Cu/Ni/sub 81/Fe/sub 19//Ta spin-valve test structures. For fields applied parallel to the bias-current direction, we observed a one-to-one correlation between the magnetoresistance and the magnetization-dependent second-harmonic intensity. The dependence of the second-harmonic intensity on magnetic field indicates that the detected second-harmonic response arises largely from the top Ni/sub 81/Fe/sub 19//Ta interface. The existence of this one-to-one correlation implies that the second harmonic depends linearly on magnetization, thus offering a method for interface-specific magnetometry.