A nanometer‐scale recording technique has been demonstrated on an amorphous GeSb2Te4film with an atomic force microscope (AFM). Data are recorded by locally changing the electrical property of the film with a conductive AFM probe. The conductance of the film is able to be increased more than one hundred times by applying a pulse voltage between the probe and the film. The recorded data are read by detecting the change of the conductance with the probe. The simultaneous measurement of the topographic and conductance images with the AFM shows that the surface topography of the recorded regions is not changed during the recording process. The smallest recorded region is 10 nm in diameter, which corresponds to a data storage density of 1 Tbit/cm2. ©1995 American Institute of Physics.