Magnetic domain walls in ferromagnetic ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_3$ films ${(T}_C\sim 260\mathrm{K})$ have been studied in the transmission electron microscope. Epitaxial films grown on ${\mathrm{SrTiO}}_3$ and ${\mathrm{NdGaO}}_3$ substrates were prepared using a focused ion beam microscope to create electron transparent areas. Energy filtered domain-wall images taken at 100 K as a function of defocus were used to determine the width of a 180° domain wall. A linear extrapolation of the inferred angular dependence of moment on position, from the wall center to ±90°, gives a wall width of $38\pm 10\mathrm{nm}$ in agreement with theoretical predictions.

• Received 4 May 2001

DOI:https://doi.org/10.1103/PhysRevB.64.172407