Tuning the interfacial spin-orbit coupling with ferroelectricity.

Detection and manipulation of spin current lie in the core of spintronics. Here we report an active control of a net spin Hall angle, θ(SHE)(net), in Pt at an interface with a ferroelectric material PZT (PbZr(0.2)Ti(0.8)O(3)), using its ferroelectric polarization. The spin Hall angle in the ultra-thin Pt layer is measured using the inverse spin Hall effect with a pulsed tunneling current from a ferromagnetic La(0.67)Sr(0.33)MnO(3) electrode. The effect of the ferroelectric polarization on θ(SHE)(net) is enhanced when the thickness of the Pt layer is reduced. When the Pt layer is thinner than 6 nm, switching the ferroelectric polarization even changes the sign of θ(SHE)(net). This is attributed to the reversed polarity of the spin Hall angle in the 1(st)-layer Pt at the PZT/Pt interface when the ferroelectric polarization is inverted, as supported by the first-principles calculations. These findings suggest a route for designing future energy efficient spin-orbitronic devices using ferroelectric control.