Noise analysis of magnetoresistive permalloy detectors

The noise characteristics of magnetoresistive bubble detectors were studied in the 0-70 °C temperature range using 1 Mbit permalloy devices. The results show that the "zero" signal noise is constant while the "one" signal noise is a function of the temperature. The main source of the "one" signal noise is the random propagation of the stripe domain rather than the switching noise of the permalloy elements. Strong correlation exists between the noise amplitude and the slope of the signal. It is proposed that the detector noise can be modeled with random changes of the phase lag of the propagating stripe.