Magnetic field sensors from polycrystalline manganites

We report on the fabrication of magnetic sensors based on bulk La0.67Sr0.33MnO3 and La0.67Ba0.33MnO3 material. The sensors were characterized at fields of 0-8 T and temperatures of 4.2-300 K. The sensors display a maximum sensitivity of similar to 200%/T at room temperature within a field range of 1-3 mT. For the sensor geometry investigated here, the low-field magnetoresistance (MR) of the sensors measured in three field orientations with respect to the sensor plane is strongly anisotropic. The high-field MR, in contrast, is found to be field-orientation independent. Periodic response of the sensor's resistance to the angle between the field and sensor-plane is demonstrated at room temperature. (C) 2001 Elsevier Science B.V. All rights reserved.