  Complex many-body interaction in perovskite manganites gives rise to a strong
competition between ferromagnetic metallic and charge ordered phases with
nanoscale electronic inhomogeneity and glassy behaviors. Investigating this
glassy state requires high resolution imaging techniques with sufficient
sensitivity and stability. Here, we present the results of a near-field
microwave microscope imaging on the strain driven glassy state in a manganite
film. The high contrast between the two electrically distinct phases allows
direct visualization of the phase separation. The low temperature microscopic
configurations differ upon cooling with different thermal histories. At
sufficiently high temperatures, we observe switching between the two phases in
either direction. The dynamic switching, however, stops below the glass
transition temperature. Compared with the magnetization data, the phase
separation was microscopically frozen, while spin relaxation was found in a
short period of time.
