High spin pumping efficiency in Fe$_{80}$Co$_{20}$/Ta bilayers

VELÁZQUEZ RODRIGUEZ, D.; JAVIER GÓMEZ; LEONARDO MORBIDEL; COSTANZO CASO, PABLO A.; JULIAN MILANO; ALEJANDRO BUTERA

JOURNAL OF PHYSICS - D (APPLIED PHYSICS)

IOP PUBLISHING LTD

Año: 2021

0022-3727

We have investigated the spin pumping phenomenon in Fe80Co20/Ta bilayers of dierent thicknessesin which the ferromagnet grows epitaxially on MgO substrates. We have obtained a Gilbertdamping constant for Fe80Co20 as low as = 1.3(1)10􀀀3, which is comparable to that obtainedfor insulating ferromagnets such as YIG. From the dependence of with the Fe80Co20 thickness, weextracted the value of the eective spin mixing conductance g"#= 5.7(3)1014 cm􀀀2. Analyzing theTa and Fe80Co20 thickness dependence of the inverse spin Hall eect (ISHE) voltage, we obtainedthe transport parameters sd= 1.1(3) nm and SH= -0.024(3). We have developed an expressionto quantify the eciency of the spin pumping phenomenon in ferromagnetic/nonmagnetic metal bilayers.The calculated eciency shows that the Fe80Co20/Ta system is up to an order of magnitudemore ecient than other metallic ferromagnetic bilayers reported in the literature.