Abstract:
Ferromagnetic resonance spectra of La1−xCaxMnO3 powders (0.1 ≤ x ≤ 0.9) have been investigated over a range of temperatures. The spectra could be fitted to a sum of two Lorentzlans for all the compositions. The intense line with a nearly constant g shows a linear decrease in linewidth with increase in temperature, while the weaker line with a variable g shows a maximum in linewidth in the TC region. The latter is also associated with a geff which depends on the composition.