Antiferromagnetic spin pumping via hyperfine interaction

Abstract

Spin pumping is an interfacial spin current generation from the ferromagnetic layer to the non-magnetic metal at its interface. The polarization of the pumped spin current s ∝ × ̇ depends on the dynamics of the magnetic moment . When the materials are based on light transition metals, mechanism behind the spin current transfer is dominated by the exchange interaction between spin of localized d-electrons and itinerant conduction electrons. In heavier transition metals, however, the interaction is not limited to the exchange interaction. The spin of the conduction electron can interact to its nuclear spin by means of hyperfine interaction, as observed in the shift of NMR frequency. By studying the spin polarization of conduction electron of the non-magnetic metallic layer due to a nuclear magnetic moment of the ferromagnetic layer, we show that the hyperfine interaction can mediate the spin pumping. The polarization of the spin current generation is shown to have a similar form J s ∝ × ̇ .

Spin–orbit torque on nuclear spins exerted by a spin accumulation via hyperfine interactions

“…Furthermore, g damp comes from the nonequilibrium part of the response function, χ 2 , which is also responsible for damping-like spintransfer torque [42] and spin pumping [40]. Contribution of dipolar interaction in g damp is smaller than Fermi contact, in accordance with [47]. The value of the total g damp is in agreement with observation [45].…”

“…A recent study demonstrated the spin-current pumping from nuclear spin waves [45,46]. In such a case, the spin transfer is mediated by the hyperfine coupling [47], which consists of dipole-dipole [5,48] and Fermi contact interactions [49].…”

Enhancement of thermal spin pumping by orbital angular momentum of rare earth iron garnet

“…While the spin pumping of Y 3 Fe 5 O 12 can be described by the dynamic of Fe magnetic moment alone [27], the total spin current generation of RY 2 Fe 5 O 12 require two magnetic sub-lattices model. Since the spin mixing conductance is shown to arise from the exchange interaction between the localized spin of ferromagnet and conduction spin of the non-magnetic metal [27,28,29…”

Effect of interfacial spin mixing conductance on gyromagnetic ratio of Gd substituted Y$_{3}$Fe$_{5}$O$_{12}$

“…In linear response regime, the exchange interaction dictates that the spin density of the conduction electron responds linearly to perturbation due to exchange interaction [4,28] (r) = ∑…”