It is important to ensure good selectivity of a single magnetic
tunnel junction storage cell within a
memory array without affecting nearby storage cells. For this purpose, this
memory array of storage cells preferably comprises a) an array of electrically conducting bit lines and electrically conducting word lines which form intersections therebetween, b) a
storage cell disposed at each of said intersections, each
storage cell comprising at least one reversible magnetic region or layer characterized by a
magnetization state which can be reversed by applying thereto a selected external
magnetic field, said reversible
magnetic layer comprising a material whose
magnetization state is more easily reversed upon a change in the temperature thereof, and c) a temperature change generator for changing the temperature of said reversible
magnetic layer of only a selected one of said array of storage cells at any moment. To select a
cell, it is preferable to select a
cell by using a brief pulse of tunnelling current between the intersecting bit and word lines at that
cell in order to provide sufficient
Joule heating to facilitate a change in the
magnetization state of its reversible
magnetic layer, which preferably comprises a ferrimagnetic material.