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Register a new userTemperature dependence of the electron spin resonance linewidth in magnetic insulators
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We analyze the temperature dependence of the electron spin resonance linewidth above the critical region in exchange-coupled magnetic insulators. The focus is on separating the contributions to the linewidth from spin-spin interactions, spin-one-phonon interactions and spin-two-phonon interactions at temperatures where the spin-spin term is constant and the one- and two-phonon terms vary as T and T^2, respectively. Taking Co3O4 as an example, we use a least squares fit over the temperature range 50 K < T < 500 K to obtain values of the three components. It is found that the spin-spin mechanism is dominant below 100 K, while the two-phonon mechanism is most important above 250 K. In the intermediate region, all three mechanisms make significant contributions.
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We provide a macroscopic theory and experimental results for magnetic resonances of antiferromagnetically-coupled ferrimagnets. Our theory, which interpolates the dynamics of antiferromagnets and ferromagnets smoothly, can describe ferrimagnetic resonances across the angular momentum compensation point. We also present experimental results for spin-torque induced ferrimagnetic resonance at several temperatures. The spectral analysis based on our theory reveals that the Gilbert damping parameter, which has been considered to be strongly temperature dependent, is insensitive to temperature. We envision that our work will facilitate further investigation of ferrimagnetic dynamics by providing a theoretical framework suitable for a broad range of temperatures.
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