This work reports remanent electric-control of spin-orbit torques (SOT) in a perpendicular ferromagnet-SrTiO3 system. Non-volatile electric-control of the sheet resistance is achieved with 1150% contrast, and two remanent resistivity states. A remanent electric-control of the SOT efficiency is demonstrated using second harmonic Hall methods, with sign inversion of the anti-damping-like effective field. These results are consistent with a combination of both intrinsic modulation of the SOT efficiency and extrinsic modulation due to the non-volatile electric-control of the current injection in the 2DEG. The non-volatile control of the SOT effective field is evidenced by reproducible inversion of the SOTs after voltage pulses initialization, opening the way to reconfigurable SOT memories and logic-gate architectures.
The link between magnetization and Spin Hall Effect (SHE) has remained mostly unclear for now. In a first part of this contribution, we study oh the presence of the magnetization affect the SHE, by performing in the weak ferromagnet NiCu Spin Pumping-FMR measurements across the ferromagnetic / paramagnetic critical temperature. We show that the high spin Hall effects which can be obtained in 3d ferromagnets seems to be independent of the magnetic phase.
In a second part, we show that the spin absorption process in a ferromagnetic material depends on the spin orientation relative to the magnetization. Using a ferromagnet to absorb the pure spin current created within a lateral spin valve, we evidence and quantify a sizable orientation dependence of the spin absorption in Co, CoFe, and NiFe. These experiments allow us to determine the spin-mixing conductance, an elusive but fundamental parameter of the spin-dependent transport.
While classical spintronics relies on the use of ferromagnetic materials to generate and detect spin currents, spin-orbitronics exploits the spin-orbit coupling (SOC) in non-magnetic systems to reach this goal. An efficient spin current detection and generation has been achieved in heavy metals such as Pt, W or Ta thanks spin to charge interconversion due to the Spin Hall Effect. However, an even larger interconversion was made possible by the use of the Direct and Inverse Edelstein Effect (EE and IEE) in systems with broken inversion symmetry at interfaces, inducing Rashba SOC.
We observed the IEE in an in interfaces-engineered high-carrier-density SrTiO3 two-dimensional electron gas (2DEG) by mean of SP-FMR. This interconversion can be modulated by the application of a gate voltage, reaching very high values thanks to the enhanced Rashba splitting due to orbital mixing, and the vicinity of the 2DEG Fermi level with an of avoided band crossing with topologically non-trivial order [1].
By combining this high interconversion efficiency with induced ferroelectric properties in SrTiO3, we show that it is possible to control the sign of the spin to charge interconversion in a non-volatile fashion by manipulating the spin orbit properties of the 2DEG through an electric control of the polarization direction [2].
This electrically controlled non-volatile interconversion sign switching opens the way to ultra-low power spintronics, in which non-volatility would be provided by ferroelectricity rather than by ferromagnetism.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.