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Electron spin resonance spectra have been studied in partially crystallized films of La(1-x)Na(x)MnO(3) (x = 0.16) in the vicinity of the para- to ferromagnetic transition. The objects of investigation were obtained by magnetron sputtering on polycrystalline Al(2)O(3) substrates held at different temperatures. It is shown that, in a regime where the paramagnetic and ferromagnetic phases coexist, the resonance conditions for one phase strongly depend on the parameters of the other phase. As a result, the resonance field of the paramagnetic phase becomes dependent on the shape of the sample, the saturation magnetization and the fraction of the ferromagnetic phase. A simple model is developed to predict the character of the changes in the resonance field of the paramagnetic phase upon the nucleation of the ferromagnetic phase.

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Ferromagnetic resonance ͑FMR͒ was used to study the influence of miscut direction on the in-plane fourfold and uniaxial magnetic anisotropies of epitaxial Fe 3 O 4 films grown on vicinal MgO ͑100͒ surfaces. In-plane angular dependent measurements at room temperature on Fe 3 O 4 films on two different miscut directions ͑miscut along ͗011͘ and ͗010͘ directions͒ of MgO showed the presence of both in-plane fourfold ͑cubic͒ and in-plane uniaxial anisotropies. Temperature dependent FMR investigations show that the in-plane fourfold anisotropy constant ͑K 4 ͒ is approximately the same for both samples at room temperature. The magnitude of K 4 increases gradually with decreasing temperature and changes sign from negative to positive values at 130 K. This behavior is consistent with that of bulk magnetite. In addition to K 4 , we find an additional uniaxial component ͑K 2 ͒, whose strength is quite different for the different miscut directions. The magnitude of K 2 shows very little or no temperature dependence. The observed differences in the magnitude of K 2 with miscut directions are related to the changes in the antiphase boundary structure and altered magnetic configurations at the boundaries.