Spin Absorption Effect at Ferromagnet/Ge Schottky-Tunnel Contacts

Abstract

We study the influence of the junction size in ferromagnet (FM)/semiconductor (SC) contacts on four-terminal nonlocal spin signals in SC-based lateral spin-valve (LSV) structures. When we use FM/Ge Schottky-tunnel junctions with relatively low resistance-area products, the magnitude of the nonlocal spin signal depends clearly on the junction size, indicating the presence of the spin absorption effect at the spin-injector contact. The temperature-dependent spin signal can also be affected by the spin absorption effect. For SC spintronic applications with a low parasitic resistance, we should consider the influence of the spin absorption on the spin-transport signals in SC-based device structures.

Room-temperature local magnetoresistance effect in n-Ge devices with low-resistive Schottky-tunnel contacts

“…Whereas further low RA values of ∼0.01 kΩ μm 2 are optimum condition for observing large MR ratios, [53][54][55] the spin absorption at the FM/Ge contacts on the spin transport might affect. 57) Thus, it is more important for enhancing the MR ratio to increase γ than to reduce r b /r N . As a possible and realistic issue, we should further explore methods for the increase in γ in the present r b /r N range.…”

A low-temperature fabricated gate-stack structure for Ge-based MOSFET with ferromagnetic epitaxial Heusler-alloy/Ge electrodes

“…41,44) The heterointerface consisting of Co 2 FeSi 0.5 Al 0.5 and n + -Ge was abruptly smooth and contact resistance was able to be controlled by tuning the number of 3.3-Å-thick Si insertion layers. 56) And then, an Au=Ti cap layer was evaporated on the top of it. To fabricate the n-Ge(111) channel area and the Co 2 FeSi 0.5 Al 0.5 =n + -Ge contacts, we patterned the above grown layers into the contact shape (50 × 50 µm 2 ) by means of conventional electron beam lithography and Ar + milling.…”