Spin current relaxation time in thermally evaporated pentacene films

TL;DR

This study measures the spin current relaxation time in thermally evaporated pentacene films, finding it to be sufficiently long for potential spintronic applications, based on experimental transport properties and diffusion length data.

Contribution

The paper provides the first estimation of spin current relaxation time in evaporated pentacene films using combined transport measurements and diffusion length analysis.

Findings

Spin current relaxation time in pentacene is approximately 150 ns.

Hole mobility in pentacene is about 8.0x10^-7 m^2/Vs.

Spin diffusion length in pentacene is around 42 nm.

Abstract

The spin current relaxation time [tau] in thermally evaporated pentacene films was evaluated with the spin-pump-induced spin transport properties and the charge current transport properties in pentacene films. Under an assumption of a diffusive transport of the spin current in pentacene films, the zero-field mobility and the diffusion constant of holes in pentacene films were experimentally obtained to be ~8.0x10^-7 m^2/Vs and ~2.0x10^-8 m^2/s, respectively. Using those values and the previously obtained spin diffusion length in pentacene films of 42{plus-minus}10 nm, the [tau] in pentacene films was estimated to be 150{plus-minus}120 ns at room temperature. This estimated [tau] in pentacene films is long enough for practical use as a spintronic material.