High field electron spin resonance measurements on La0.67Ca0.33MnO3 thin films

La0.67Ca0.33MnO3 thin films of different thicknesses have been studied by high frequency–high magnetic field ESR. The thinner one (150 nm) presents one single ESR line revealing a good homogeneity. We have determined its gyromagnetic tensor, which presents a slight anisotropy as regards the film plane: g∥=1.97 and g⊥=1.99. These values are in agreement with spin–orbit coupling. The magnetic anisotropy is uniaxial, within the film plane. The anisotropy field at low temperature is 0.07 T, a magnitude comparable to that observed in bulk compounds.