7/8/2023 0 Comments Spin pumping apl hof fmanBecause the temperature-dependent Gd magnetization ( M Gd) is stronger than the Py magnetization ( M Py), there exists a transition from the Gd-aligned phase (| M Py| | M Gd|) at high temperatures. In an artificial ferrimagnet of Py/Gd/Py/Gd/Py/Pt multilayer in which the Py and Gd are antiferromagnetically coupled, the net magnetization always precesses around a magnetic field with right-handed chirality, the same as the magnetization precession in a ferromagnet. One recent experiment designed a cleaver method in which spin pumping from Py into Pt layers by left-handed and right-handed Py magnetic precessions were realized independently 9. To address this fundamental issue, it is critical to realize an isolated left-handed spin precession and to study its spin pumping in an experiment. The angular momentums carried by m 1 and m 2 precessions are both described by the same damping term for spin current transmission in AFM insulators 7, 8. Pure spin current, which consists of only the flow of spin without the flow of charge, mostly comes from the so-called spin pumping where the precession of a magnetic moment pumps a spin current into a neighboring layer due to the extra damping of \(\triangle \alpha \vec\) is valid for both right-handed and left-handed spin pumpings 6. Specifically, the experiment needs to answer if opposite chiralities of the spin precession should pump opposite spin polarizations of the spin current?Īkin to electric current, which is a flow of charge, spin current is a flow of spin that delivers angular momentum in space. Since nature selects only right-handed spin precession in ferromagnets, it is an experimental challenge to address this fundamental issue by investigating spin pumping from right-handed and left-handed spin precessions independently. Specifically, it is unclear whether the right-handed and left-handed spin precessions pump the same spin current. Nonetheless, the role of spin-precession chirality in spin pumping remains a fundamental issue. Right-handed spin pumping has been successfully described by a phenomenological spin-damping term that the damped angular momentum of the spin precession converts into a spin current 2. Such right-handed spin precession could pump a pure spin current and create an electric voltage in neighboring layers, thus opening new opportunities for spintronics development 1. Magnons in ferromagnetic materials, the bosonic quasiparticles of collective spin excitations, have the unique character that only right-handed chirality exists in the spin precession around its equilibrium axis. Chirality (or handedness) is an important concept that distinguishes a system from its mirror images.
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