Thickness dependence of spin pumping at YIG/Pt interface

ABSTRACT We report Y 3 Fe 5 O 12 thickness dependence of spin pumping, spin current generation from magnetization dynamics, in magnetic insulator Y 3 Fe 5 O 12 /metal Pt bilayer films. We prepared different thickness Y 3 Fe 5 O 12 films by the metal-organic decomposition method and measured the electromotive force due to the inverse spin Hall effect induced by the spin pumping in Y 3 Fe 5 O 12 /Pt films. We found that spin-mixing conductance, or spin-pumping efficiency, Y 3 Fe 5 O 12 /Pt films constant for the di fferent thickness is almost same in various Y 3 Fe 5 O 12 thickness. This result is consistent with the prediction of the spin pumping; the spin-pumping efficiency is determined by the exchange interaction at the Y 3 Fe 5 O 12 /Pt interface. Keywords: Spintronics, Spin pumping, Spin current, Inverse spin Hall effect 1. INTRODUCTION There has been great interest in the field of spintronics [1]-[37], which is a new device technology for efficient magnetic memories and computing devices base d on electron spins. In this field, the generation and detection of a spin current [1]-[4], [7]-[11], [15], [16], [27]-[33], [35], [36], a flow of spin angular momentum in a solid, plays an important role. One method for generating spin currents is the spin pumping [5], [6], [12]-[14], [17]-[26], [34], [37]. The spin pumping generates a spin current from magnetization precession driven by the ferromagnetic resonance (FMR) or spin-wave resonance at ferro(ferri)magnetic/paramagnetic interfaces. The strength of the spin pumping is proportional to the spin-mixing conductance [20], [26]. Recently, spin pumping was observed at ferrimagnetic insulator Y