Angular Dependence of Low-Frequency Noise in Al$_{2}$O$_{3}$-Based Magnetic Tunnel Junction Sensors With Conetic Alloy

Z. Q. Lei, T. Zeng, G. Feng, P. J. Chen, P. T. Lai, Philip W. T. Pong
2012 IEEE transactions on magnetics  
We demonstrated the noise performances of Al2O3-based magnetic tunnel junction sensors (MTJs) in the low-frequency regimes. Conetic alloy Ni77Fe14Cu5Mo4 was deposited as both the MTJ pinned layer and free layer because of its superb magnetically soft properties. A rotating magnetic field was employed to investigate the angular dependence of the MTJ low-frequency noise. Hooge parameter was applied for parameterizing the low-frequency noise. The measurement results demonstrate that the Hooge
more » ... that the Hooge parameters are angular-dependent and they exhibit a linear relation with respect to the angular magnetoresistive susceptibility. It can be also observed that the Hooge parameters possess a higher value when the Conetic MTJs are in the region of antiparallel state. These results indicate that the magnetic fluctuations in the ferromagnetic layers contribute to the low-frequency noise level in Conetic MTJ sensors. Index Terms-Conetic, low-frequency noise, magnetic sensors, magnetic tunnel junction (MTJ).
doi:10.1109/tmag.2012.2196688 fatcat:zowej2fn6rgitnp3k6fsqfi4hu