Threshold properties of 1, 2 and 4 µm multilayer magneto-resistive memory cells

The threshold and memory properties of nominal 1, 2 and 4 μm wide multilayer permalloy magneto-resistive elements have been examined. The study shows that these elements can be used in two nondestructive readout (NDRO) modes in word organized non-violatile memory configurations. One mode requires just a M-R sense and a word line. It also requires a "block" word erase. The other coincident write-mode requires two word lines and a M-R sence line. Signal level is a function of element resistance, sense current, magnetoresistance, and operating mode. The NDRO signal level for a typical 1.3 μm by 100 μm element in the coincident write-mode was 10 mv.