https://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloadshttps://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/power-dependent-characteristics-of-spin-current-transfer-in-metal-bilayer-devices-under-high-power-pulse-excitationESR Peer-Reviewed ArticlesTue, 31 May 2022 13:39:26 GMT

The power-dependent transfer characteristics of spin currents at the interface of the permalloy/Pt bilayer device were investigated over a wide power range

<h2>Abstract</h2> <p>The power-dependent transfer characteristics of spin currents generated at the interface of the permalloy/Pt bilayer device have been investigated over a wide power range from a few tens of milliwatt to 396 W. We built a high-power pulse excitation system for spin pumping, which achieves large electromotive force (EMF) values of 10 mV at 396 W excitation through the inverse spin Hall effect (ISHE) and demonstrates that the EMF generation after pulse excitation is very fast. Under strong pulse microwave excitation more than 80 W, the EMF spectrum exhibits an asymmetrical lineshape, which is well reproduced by simulations that take into account the fold-over effect due to the nonlinear ferromagnetic resonance excitation. The maximum output power at an external load through spin pumping and the ISHE is shown to increase in proportion to the square of the input microwave power (<i>P</i>_in) in the power range below 80 W. This power generation proportional to <i>P</i>_in² is unique to spin current-mediated power flow. In the strong excitation regime with the fold-over type EMF spectra, the EMF values of the peak magnetic field position are found to increase less linearly due to spectral broadening. This feature can be used for power generation that increases nonlinearly with respect to the input excitation power, where the nonlinearity is adjusted by varying the magnetic field position.</p> <h2>Please click this link to view the article:  <a href="https://doi.org/10.1021/acsami.2c03418">https://doi.org/10.1021/acsami.2c03418</a></h2> https://www.jeolusa.com/RESOURCES/Analytical-Instruments/Documents-Downloads/quantifying-power-flow-processes-mediated-by-spin-currentsESR Peer-Reviewed ArticlesFri, 30 Apr 2021 08:25:40 GMT

The power flow process mediated by spin current in the bilayer device consisting of ferromagnetic metal (FM) and nonmagnetic metal (NM) layers is examined by realizing experimental evaluations for each process from the microwave absorption to electromotive force (EMF) output. The absorption power by ferromagnetic resonance (FMR) of the thin FM layer during the EMF output is directly measured in operando using an antenna probe system. The transfer efficiency of the absorption power into the NM layer by spin pumping is estimated from strict linewidth evaluation of EMF spectra. The maximum transfer efficiency of the spin pumping power to the external load via the inverse spin Hall effect is determined to be 4.2 × 10–8 under 162 mW microwave irradiation using an analysis model assuming a parallel circuit. The main factors reducing the efficiency are found to be low resistivity of the NM layer and the interface loss. These quantifications are important as a first step to consider the efficient transfer of spin energy mediated by spin currents.

<h2 id="Abstract">Abstract</h2> <p><img alt="Abstract Image" src="/Portals/2/images/AI/el0c01138_0007.gif" /></p> <p>The power flow process mediated by spin current in the bilayer device consisting of ferromagnetic metal (FM) and nonmagnetic metal (NM) layers is examined by realizing experimental evaluations for each process from the microwave absorption to electromotive force (EMF) output. The absorption power by ferromagnetic resonance (FMR) of the thin FM layer during the EMF output is directly measured in <i>operando</i> using an antenna probe system. The transfer efficiency of the absorption power into the NM layer by spin pumping is estimated from strict linewidth evaluation of EMF spectra. The maximum transfer efficiency of the spin pumping power to the external load via the inverse spin Hall effect is determined to be 4.2 × 10^–8 under 162 mW microwave irradiation using an analysis model assuming a parallel circuit. The main factors reducing the efficiency are found to be low resistivity of the NM layer and the interface loss. These quantifications are important as a first step to consider the efficient transfer of spin energy mediated by spin currents.</p> <h3>Click Link to Read More: <a href="https://doi.org/10.1021/acsaelm.0c01138" target="_blank" title="DOI URL">https://doi.org/10.1021/acsaelm.0c01138</a></h3>