This work describes the design and fabrication of a giant magnetoresis
tive (GMR) magnetometer for earth field measurements. The magnetometer
uses sputtered thin film permanent magnets to provide a bias field. I
t is shown that a simple model can be used to predict the sensitivity
and optimum bias field requirements for the device. The GMR magnetomet
er is compared to a similar device which utilises the anisotropic magn
etoresistance effect and is shown to have a superior signal to noise r
atio and dynamic range. (C) 1997 Elsevier Science S.A.