Efficient Injection and Detection of Out-of-Plane Spins via the Anomalous Spin Hall Effect in Permalloy Nanowires

Abstract

We report a novel mechanism for the electrical injection and detection of out-of-plane spin accumulation via the anomalous spin Hall effect (ASHE), where the direction of the spin accumulation can be controlled by manipulating the magnetization of the ferromagnet. This mechanism is distinct from the spin Hall effect (SHE), where the spin accumulation is created along a fixed direction parallel to an interface. We demonstrate this unique property of the ASHE in nanowires made of permalloy (Py) to inject and detect out-of-plane spin accumulation in a magnetic insulator, yttrium iron garnet (YIG). We show that the efficiency for the injection/detection of out-of-plane spins can be up to 50% of that of in-plane spins. We further report the possibility to detect spin currents parallel to the Py/YIG interface for spins fully oriented in the out-of-plane direction, resulting in a sign reversal of the nonlocal magnon spin signal. The new mechanisms that we have demonstrated are highly relevant for spin torque devices and applications.

Modulation of magnon spin transport in a magnetic gate transistor

“…2(b). The detection of non-local magnon transport at the Py strip occurs via a combination of ISHE and the inverse anomalous spin Hall effect (IASHE), resulting in a detection efficiency that depends on the orientation of M Py and leading to a line shape consistent with previous reports [14,15]. A modulation of more than 210% in the R 1f NL measured by the Py detector is observed, which occurs due to the detection mechanism being dominated only by ISHE at low B and evolving into being composed by both IASHE and ISHE at high B.…”

“…Note that due to a low coercive field of our YIG film (< 1 mT) [13], M YIG is essentially always oriented along the x-axis in our measurements. Besides, any possible interfacial exchange interaction between Py and YIG doesn't play a significant role [14,15] and therefore M YIG and M Py can move freely with respect to each other. By changing the magnitude of B, R 1f NL was modulated, reaching a minimum value at |B| ≈ 50 mT, corresponding to the tilting of M Py along the in-plane hard axis direction (x-axis) of the magnetic gate.…”

Intrinsic Half‐Metallicity in 2D Ternary Chalcogenides with High Critical Temperature and Controllable Magnetization Direction

“…In particular, a gap near the Fermi level opens at K point (highlight in red box) with the energy splitting Δ E ′ about 32 meV, which is about hundred times larger than Zeeman splitting under external magnetic field. The remarkable change in band structure induced by spin reorientation is particularly useful for logic operation in spin transistors and spin‐torque applications . Therefore, developing a practical method to control the spin direction is highly desired.…”

Unidirectional Pumping of Phonons by Magnetization Dynamics

“…1. Similar configurations on magnetic substrates led to the electrical detection of diffuse magnon transport [22,23] and discovery of nonreciprocal magnon propagation [24], i.e., the generation of a unidirectional spin current in half space [25,26]. Magnetic stray fields of the magnetization dynamics also generate chiral electron [27] and waveguide photon [28] transport.…”