Microwave resonance and propagation in nonsaturated ferromagnetic media. I. Magnetic resonance in single crystal ferrite platelets

摘要

We present calculations of the magnetic resonance frequencies of multidomain single crystal ferrite platelets. The theoretical results are compared to our microwave ferromagnetic resonance (FMR) experiments performed at frequencies between 8 and 40 GHz and magnetic fields between 0 and 20 kOe. Good agreement is found between theory and experiment with no adjustable parameters. In the calculation we have included the effect of a change in the periodicity of regularly patterned domain structures on the FMR frequencies. The variation in periodicity is seen to influence the measured FMR frequencies f for magnetic fields H applied normal to the platelet plane in agreement with our calculations. The predicted variation in periodicity agrees with our visual observation of domain structures in the sample. The in‐plane FMR data is also in reasonable agreement with calculations. Although the measured frequency and field FMR linewidths agree well with our calculations in magnetically saturating fields, the agreement is less satisfactory in the nonsaturated region.