MTJ sensoring including domain stable free layer

A magnetic field sensor having a domain stable free layer, comprising: an antiferromagnetic layer on a lower conductive layer; a pinned magnetic reference layer, having a magnetization direction, on said antiferromagnetic layer; a separation layer on said magnetic reference layer; a magnetic free layer on said separation layer; a capping layer on said magnetic free layer; said magnetic reference, separation, free, and capping layers having the form of a plurality of independent sensor stacks, each such stack having, in plan view, a width dimension along a first axis and a length dimension along a second axis, with a length-to-width ratio sufficient to support an anisotropy field, and a length dimension no greater than a domain wall width and perpendicular to said pinned magnetization direction whereby all free layers of said sensor stacks are domain stable when exposed to a magnetic field; said lower conductive layer having the form of a bottom electrode that is common to all said sensor stacks; a dielectric layer that fills all space between said sensor stacks, including covering all sidewalls; and a top electrode that contacts said capping layer whereby it is common to all said sensor stacks.