Oxygen concentration measurement with GMR

An oxygen sensing method comprising:

• generating a magnetic field within a giant magnetoresistance device and an examination region;
• perturbing the magnetic field overlapping the giant magnetoresistance device by introducing a concentration of oxygen into the examination region;
• interposing an oxygen barrier between the giant magnetoresistance device and the examination region such that oxygen in the examination region does not reach the giant magnetoresistance device;
• measuring the perturbation of the magnetic field using the giant magnetoresistance device;
• and
• outputting an oxygen concentration value determined based on the measured magnetic field perturbation.

An oxygen sensor comprising:

• a chip including:
• (i) two parallel electrically conductive traces disposed on or in a planar front side of the chip,
• (ii) a planar giant magnetoresistance device parallel with and disposed on or in the planar front side of the chip and centered between the two parallel electrically conductive traces, and
• (iii) an oxygen barrier disposed on the planar front side of the chip and isolating the planar giant magnetoresistance device from ambient oxygen;
• and
• a detector module configured to:
• (i) drive electric current through each of the two electrically conductive traces in the same direction such that electrical currents flowing in the two electrically conductive traces cooperatively generate a magnetic field component within and oriented parallel with the planar giant magnetoresistance device, and
• (ii) generate an oxygen concentration signal based on the magnetic field component within the magnetic field sensor oriented parallel with the planar giant magnetoresistance device.