Spin wave measurements have been carried out in ferromagnetic (F) La(1-x)(Sr,Ca)(x)MnO(3) with x(Sr) = 0.15, 0.175, 0.2, 0.3, and x(Ca) = 0.3. In all q directions, close to the zone boundary, the spin wave spectra consist of several energy levels, with the same values in the metallic and the x approximately 1/8 doping ranges. For x(Sr) = 0.15, the data are quantitatively interpreted in terms of quantized spin waves within 2D ordered F domains or clusters of 4a size. The same picture holds in the metallic state with, however, disordered clusters embedded in a 3D F matrix.
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