We report on a magnetic field sensor based on CoFeB/MgO/CoFeB magnetic tunnel
junctions. By taking advantage of the perpendicular magnetic anisotropy of the
CoFeB/MgO interface, the magnetization of the sensing layer is tilted
out-of-plane which results in a linear response to in-plane magnetic fields.
The application of a bias voltage across the MgO tunnel barrier of the field
sensor affects the magnetic anisotropy and thereby its sensing properties. An
increase of the maximum sensitivity and simultaneous decrease of the magnetic
field operating range by a factor of two is measured. Based on these results,
we propose a voltage-tunable sensor design that allows for active control of
the sensitivity and the operating filed range with the strength and polarity of
the applied bias voltage.Comment: 4 pages, 4 figures, lette
