Spin-current injection and detection in κ-(BEDT-TTF)2Cu[N(CN)2]Br

Abstract

Spin-current injection into an organic semiconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br film induced by the spin pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage signal was found to appear in the κ-(BEDT-TTF)2Cu[N(CN)2]Br film. Magnetic-field-angle dependence measurements indicate that the voltage signal is governed by the inverse spin Hall effect in κ-(BEDT-TTF)2Cu[N(CN)2]Br. We found that the voltage signal in the κ-(BEDT-TTF)2Cu[N(CN)2]Br/YIG system is critically suppressed around 80 K, around which magnetic and/or glass transitions occur, implying that the efficiency of the spin-current injection is suppressed by fluctuations which critically enhanced near the transitions.

Spin pumping into superconductors: A new probe of spin dynamics in a superconducting thin film

“…Because the spin pumping relies only on the spin dynamics and thus enables a charge-free spin injection [14], by now it is widely used as a versatile spin injection method. Indeed, the target materials range from normal metals [15][16][17][18][19][20][21][22], semiconductors [14,[23][24][25], magnetic metals [26][27][28], and insulators [29], to more exotic systems such as graphene [30,31], organic materials [32,33], a topological insulator [34], and a Rashba system [35]. Given this background, it is worth investigating and clarifying the nature of spin pumping into superconductors.…”

Effective spin Hall properties of a mixture of materials with and without spin-orbit coupling: Tailoring the effective spin diffusion length

“…It is much bigger than the radius, a, but much smaller than the sample width, L, which allows to replace the sum by the integral Eq. (20).…”

“…It serves as a tool to detect whether or not the spin current is injected into a nonmagnetic material from an ac-driven ferromagnet in the course of spin pumping. Most recently [18][19][20][21] the pumped spin currents in certain polymers were registered via inverse spin Hall voltage which they induced in Pt electrode located at some distance from the interface with ferromagnet.…”

Spin pumping from a ferromagnet into a hopping insulator: Role of resonant absorption of magnons

“…To make connection to the experimental papers Refs. [23][24][25][26], below we calculate the magnitude and orientation of the dc field where the anomalous behavior of ISHE voltage takes place. Such behavior takes place when two conditions are met: The Zeeman splitting of the localized states is equal to ω, and ω = ω FMR .…”

“…Microscopic treatment of this scattering 21,22 assumes that electrons of the normal layer impinging on the interface with ferromagnet are plane waves. On the other hand, in a number of recent papers [23][24][25][26] spin pumping into organic materials sandwiched between ferromagnet and Pt has been reported. Strong temperature dependence of the resistance in these materials 27 suggests that the charge transport is due to hopping of polarons 24,26 , so that the description of pumping based on plane waves does not apply.…”