Reduced interface reaction during the epitaxial Fe growth on InAs for high efficiency spin injection

Abstract

We have investigated Fe/InAs interfaces for two different growth temperatures of Fe and the effect on the spin injection properties through an Fe/InAs junction. Secondary ion mass spectroscopy and transmission electron microscopy studies of the Fe/InAs interfaces revealed that Fe films grown at 175°C clearly suffer from increased reaction and out-diffusion of semiconductor constituents compared to those grown at 23°C. The lower temperature samples showed an increased degree of spin polarization of 18%-20% which translates to 36%-40% of spin injection efficiency assuming selection rules between heavy and light holes in the p-type InAs substrate. It is close to the spin polarization of 40%-45% in an Fe spin injector itself.

Thermodynamic Calculation of Phase Equilibria in As-Fe-In Ternary System Based on CALPHAD Approach

“…[1][2][3] Fe/InAs hybrid structure has attracted attention as a candidate for realizing high spin injection efficiency. [4][5][6][7] The spin injection efficiency is critically dependent on the interface quality of the hybrid structure. Considerable efforts have been devoted to optimize the process parameters during Molecular Beam Epitaxy (MBE) growth of Fe film on the semiconductors.…”

Micromagnetic simulation of magnetization reversal process and stray field behavior in Fe thin film wire

“…5 has been observed in a device with the electrode consisting of Fe thin film wire with a thickness of 30− 40 nm and a width of 1 − 2 m. Although an accurate estimation on spin injection efficiency requires quantitative knowledge about the external field dependence of the micromagnetic state in the electrode, such field dependence in the Fe thin film wire employed in Ref. 5 remains to be clarified. The experimental observation of the external field dependence of a magnetic domain structure in a ferromagnetic thin film generally involves a technical difficulty to measure a weak magnetic contrast at a finite external field and most of the domain imaging studies for the Fe film have been carried out at zero external field.…”

“…The high efficient spin injection in Ref. 5 has been observed in a device with the electrode consisting of Fe thin film wire with a thickness of 30− 40 nm and a width of 1 − 2 m. Although an accurate estimation on spin injection efficiency requires quantitative knowledge about the external field dependence of the micromagnetic state in the electrode, such field dependence in the Fe thin film wire employed in Ref. 5 remains to be clarified.…”

“…[1][2][3] The Fe/InAs structure is among the most promising FM/SC structures enabling decent Ohmic contact without thermal reaction process at the interface. 4 A recent work by Yoh et al 5 has demonstrated the possibility of realizing a high efficient spin injection in the Fe/InAs structure. It is to be noted that micromagnetic details, such as magnetic domain pattern and domain wall structure in ferromagnetic electrode, are of critical relevance to the spin injection phenomena.…”

“…[17][18][19][20][21] In this article, we report the micromagnetic simulation for the magnetization reversal process in the Fe thin film wire utilized in Ref. 5.…”