Spin Wave Excitation, Detection, and Utilization in the Organic‐Based Magnet, V(TCNE)_x (TCNE = Tetracyanoethylene)

Abstract

Spin waves, quantized as magnons, have low energy loss and magnetic damping, which are critical for devices based on spin‐wave propagation needed for information processing devices. The organic‐based magnet [V(TCNE)x; TCNE = tetracyanoethylene; x ≈ 2] has shown an extremely low magnetic damping comparable to, for example, yttrium iron garnet (YIG). The excitation, detection, and utilization of coherent and non‐coherent spin waves on various modes in V(TCNE)x is demonstrated and show that the angular momentum carried by microwave‐excited coherent spin waves in a V(TCNE)x film can be transferred into an adjacent Pt layer via spin pumping and detected using the inverse spin Hall effect. The spin pumping efficiency can be tuned by choosing different excited spin wave modes in the V(TCNE)x film. In addition, it is shown that non‐coherent spin waves in a V(TCNE)x film, excited thermally via the spin Seebeck effect, can also be used as spin pumping source that generates an electrical signal in Pt with a sign change in accordance with the magnetization switching of the V(TCNE)x. Combining coherent and non‐coherent spin wave detection, the spin pumping efficiency can be thermally controlled, and new insight is gained for the spintronic applications of spin wave modes in organic‐based magnets.

Unconventional Spin Pumping and Magnetic Damping in an Insulating Compensated Ferrimagnet

“…Spin current injection by incoherent spin waves can be triggered by applying a thermal gradient across the interface, via an effect called longitudinal SSE. [52,53] As schematically shown in Figure 4e, an insulating SiO 2 layer was heated by a Ti/Pt strip with a charge current, giving rise to a temperature gradient (∇T) along the z-axis. The incoherent spin waves induced by the ∇T via the SSE carry spin angular momentum into the adjacent Pt layer.…”

Distinguishing spin pumping from spin rectification in lateral spin pumping device architectures based on doped organic semiconductors

“…To avoid this, it is necessary to minimize SREs and/or use a material that exhibits efficient spin transport, but is not electrically conducting. Some promising candidates include organicbased magnet V(TCNE) x (with x ≈ 2) [38], [39] or inorganic magnetic oxides such as YIG [40].…”

Distinguishing spin pumping from spin rectification in organic semiconductor-based lateral spin pumping device architectures

“…To avoid this, it is necessary to minimize SREs and/or use a material that exhibits efficient spin transport, but is not electrically conducting. Some promising candidates include organicbased magnet V(TCNE) x (with x ≈ 2) [36], [37] or inor- ganic magnetic oxides such as YIG [38].…”