LOW-TEMPERATURE MAGNETIC FORCE MICROSCOPY OF COLOSSAL MAGNETORESISTIVE FILMS

We show a detailed magnetic force microscope study of the magnetic dom ain behavior in La1-xCaxMnO3 films under the influence of temperature, topographic sample defects and external magnetic field. At low temper atures, typically about 140 degrees below T-c = 245 K, domains were st rongly coupled to each other, but could still be affected by thermal f luctuations. As we warmed the sample up, domains became highly mobile near T-c. Near T-c, sample scratches were able to capture nearby domai ns, whereas they did not affect domains when temperature is much lower than T-c. Above T-c all domains disappeared, with some of them disapp earing earlier.