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تسجيل مستخدم جديدTemperature dependence of the magnon spin diffusion length and magnon spin conductivity in the magnetic insulator yttrium iron garnet
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We present a systematic study of the temperature dependence of diffusive magnon spin transport, using a non-local device geometry. In our measurements, we detect spin signals arising from electrical and thermal magnon generation, and we directly extract the magnon spin diffusion length $lambda_m$ for temperatures from 2 to 293 K. Values of $lambda_m$ obtained from electrical and thermal generation agree within the experimental error, with $lambda_m=9.6pm0.9$ $mu$m at room temperature to a minimum of $lambda_m=5.5pm0.7$ $mu$m at 30 K. Using a 2D finite element model to fit the data obtained for electrical magnon generation we extract the magnon spin conductivity $sigma_m$ as a function of temperature, which is reduced from $sigma_m=5.1pm0.2times10^5$ S/m at room temperature to $sigma_m=0.7pm0.4times10^5$ S/m at 5 K. Finally, we observe an enhancement of the signal originating from thermally generated magnons for low temperatures, where a maximum is observed around $T=7$ K. An explanation for this low temperature enhancement is however still missing and requires additional investigations.
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