Scanning magnetoresistance microscopy of La0.67Sr0.33MnO3 films

We have developed a magnetic imaging scheme using the magnetoresistive spin valve head in a de bias mode as a sensing element. By scanning the head in contact with the sample we obtain a submicron spatial resolution map of th e normal component of the magnetic field in the temperature range 4.2-300 K . The writing element of the sensor can be used to alter the local magnetic structure in a controlled way. This technique was applied to image the mag netic domain structure down to 77 K in patterned thin films of La0.67Sr0.33 MnO3, known fur their colossal magnetoresistance. A reorientation of single or multiple domains in the films was accomplished by applying a local magn etic field with the writing element, while the effect on magnetotransport w as monitored with the simultaneous measurement of current-voltage character istics. (C) 1998 American Institute of Physics. [S0021-8979(98)27911-4].