Strong Crystallographic Influence on Spin Hall Mechanism in PLD-Grown IrO2 Thin Films.

Pilar Jiménez-Cavero,Luis Morellón,Pedro A Algarabel,M Ricardo Ibarra,Jorge Ara-Arteaga,Irene Lucas

doi:10.3390/nano11061478

Pilar Jiménez-Cavero, Luis Morellón + Show 4 more

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https://doi.org/10.3390/nano11061478

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Abstract

Spin-to-charge conversion is a central process in the emerging field of spintronics. One of its main applications is the electrical detection of spin currents, and for this, the inverse spin Hall effect (ISHE) has become one of the preferred methods. We studied the thickness dependence of the ISHE in iridium oxide (IrO) thin films, producing spin currents by means of the spin Seebeck effect in FeO/IrO bilayers prepared by pulsed laser deposition (PLD). The observed ISHE charge current density, which features a maximum as a consequence of the spin diffusion length scale, follows the typical behaviour of spin-Hall-related phenomena. By fitting to the theory developed by Castel et al., we find that the spin Hall angle scales proportionally to the thin film resistivity, , and obtains a value for the spin diffusion length of nm. In addition, we observe a negative for every studied thickness and temperature, unlike previously reported works, which brings the possibility of tuning the desired functionality of high-resistance spin-Hall-based devices. We attribute this behaviour to the textured growth of the sample in the context of a highly anisotropic value of the spin Hall conductivity in this material.

Highlights

The spin Hall effect (SHE) refers to the creation of a spin current transverse to a charge current in a nanometric metallic material [1,2,3,4,5]
We obtained the value of the spin diffusion length of IrO2 and found that the spin Hall angle is proportional to the longitudinal charge resistivity, θSH ∝ ρc ; equivalently, the value of σSH is constant and independent of the longitudinal charge conductivity σc, and ρSH scales as ρSH ∝ ρ2c (see Equations (2) and (3))
The analysis of the obtained data within the theoretical model allowed us to establish that the spin Hall angle scales with the longitudinal charge resistivity as θSH ∝ ρc, which excludes a predominant role of skew scattering in the inverse spin Hall effect (ISHE)

Summary

Introduction

The spin Hall effect (SHE) refers to the creation of a spin current transverse to a charge current in a nanometric metallic material [1,2,3,4,5]. We obtained the value of the spin diffusion length of IrO2 and found that the spin Hall angle is proportional to the longitudinal charge resistivity, θSH ∝ ρc ; equivalently, the value of σSH is constant and independent of the longitudinal charge conductivity σc , and ρSH scales as ρSH ∝ ρ2c (see Equations (2) and (3)).

Results

Conclusion