Magnetic resonance technique may successfully be applied to determine some basic parameters such as g-factor, magnetization M_{s} or anisotropy energy constant K_{u} in thin magnetic films. These parameters are obtained from a ferromagnetic resonance experiment when uniform precession of M_{s} takes place. From spin-wave resonance one may extract very valuable information on the exchange constant A or the surface conditions characterized by the surface anisotropy energy (or pinning parameters ρ). In fact, it is only spin-wave resonance or similar techniques which allow for measurements of A, ρ or the coupling constant K_{c} between ferromagnetic sublayers in multi-layered structure. The magnetic phase diagram, temperature dependence of the spin-waves stiffness constant, and the anisotropy energy constant may also be listed as less common examples of spin-wave resonance technique application for the investigation of thin films. This paper presents a theoretical approach to typical examples of experimental results and their interpretation from spin-wave resonance measurements.
Magnetic properties of polycrystalline thin films of chromium chalcogenide spinels (CdCr_{2}Se_{4} lightly doped with indium and CdCr_{2x}In_{2-2x}Se_{4}) were studied. The ferromagnetic (FMR) and spin-wave resonance (SWR) techniques were used to investigate the temperature dependences of both the spin-wave stiffness constant D and the saturation magnetization M_{s}. The resonance spectra were recorded in the temperature range extending from 4.2 K to 300 K. The influence of indium concentration on M_{s}(T) and D(T) was studied. It was shown that lightly doped samples (In/Cd < 1% at.) exhibited the ferromagnetic ordering with M_{s}(T) and D(T) being the linear functions of T^{3/2} and T^{5/2}, respectively. Higher concentration of indium produced the reentrant transition and spin-glass state of magnetic ordering in CdCr_{2x}In_{2-2x}Se_{4}. The temperature dependence of M_{s} was also found from the FMR data for these two magnetic phases.
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