Dynamic heating in submicron size magnetic tunnel junctions with exchange biased storage layer

The dynamic heating of submicron size junctions developed for the thermomagnetic write scheme was investigated. The dependency of the heating power density with the voltage pulse width $\left(\Delta t\right)$ was measured and shows a $[1-\exp (-\Delta t∕t0)]$ phenomenological variation in the investigated range of pulse widths $(5\mathrm{ns}–1\mathrm{s})$ . For submicron junction areas and constant pulse width, the heating power required for writing decreases as the junction area is reduced. The thermomagnetic write scheme was demonstrated through cycling of the cell between the two low and high resistance levels. This scheme was also shown to be insensitive to stray magnetic fields even in absence of any magnetic shielding of the memory.