All-Heusler giant-magnetoresistance junctions with matched energy bands and Fermi surfaces

TL;DR

This paper proposes an all-Heusler giant magnetoresistance junction design with matched energy bands and Fermi surfaces, leading to high spin-filtering efficiency and superior magnetoresistance performance for advanced data storage devices.

Contribution

It introduces a novel all-Heusler GMR architecture with systematic first-principles analysis demonstrating its advantages over traditional structures.

Findings

Matched energy bands and Fermi surfaces enhance spin-injection efficiency.

All-Heusler architecture shows higher GMR ratios than conventional structures.

Transport calculations confirm superior electronic properties of the proposed design.

Abstract

We present an all-Heusler architecture which could be used as a rational design scheme for achieving high spin-filtering efficiency in the current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices. A Co2MnSi/Ni2NiSi/Co2MnSi trilayer stack is chosen as the prototype of such an architecture, of which the electronic structure and magnetotransport properties are systematically investigated by first principles approaches. Almost perfectly matched energy bands and Fermi surfaces between the all-Heusler electrode-spacer pair are found, indicating large interfacial spin-asymmetry, high spin-injection efficiency, and consequently high GMR ratio. Transport calculations further confirms the superiority of the all-Heusler architecture over the conventional Heusler/transition-metal(TM) structure by comparing their transmission coefficients and interfacial resistances of parallel conduction electrons, as well as the macroscopic current-voltage (I-V) characteristics. We suggest future theoretical and experimental efforts in developing novel all-Heusler GMR junctions for the read heads of the next generation high-density hard disk drives (HDDs).