Spincaloric properties of epitaxial Co${}_2$MnSi/MgO/Co${}_2$MnSi magnetic tunnel junctions

Abstract

The electronic transport and spincaloric properties of epitaxial magnetic tunnel junctions with half-metallic Co${}_2$MnSi Heusler electrodes, MgO tunneling barriers, and different interface terminations are investigated by using first-principles calculations. A new approach to spincaloric properties is presented that circumvents the linear response approximation inherent in the Seebeck coefficient and compared to the method of Sivan and Imry. This approach supports two different temperatures in the two electrodes and provides the exact current and/or voltage response of the system. Moreover, it accounts for temperature-dependent chemical potentials in the electrodes and finite-bias effects. We find that especially the former are important for obtaining qualitatively correct results, even if the variations of the chemical potentials are small. It is shown how the spincaloric properties can be tailored by the choice of the growth conditions. We find a large effective and spin-dependent Seebeck coefficient of $-65$ $\mu$V/K at room temperature for the purely Co-terminated interface. We suggest to use such interfaces in thermally operated magnetoresistive random access memory modules, which exploit the magneto-Seebeck effect, to maximize the thermally induced readout voltage.

arXiv comment12 pages, 13 figures

References in corpus (15)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Spintronics: Fundamentals and applications
• Slater-Pauling Behavior of the Half-Ferromagnetic Full-Heusler Alloys
• Seebeck Effect in Magnetic Tunnel Junctions
• Ballistic conductance of magnetic Co and Ni nanowires with ultrasoft pseudo-potentials
• Thermal collapse of spin-polarization in half-metallic ferromagnets
• The effect of the spin-orbit interaction on the band gap of half-metals
• Non-quasiparticle states in Co${}_2$MnSi evidenced through magnetic tunnel junction spectroscopy measurements
• Spin caloritronics in magnetic tunnel junctions: Ab initio studies
• Seebeck coefficients of half-metallic ferromagnets
• GW study of the half-metallic Heusler compounds Co2MnSi and Co2FeSi
• Structural stability, magnetic and electronic properties of Co2MnSi(001)/MgO heterostructures: A density functional theory study
• Interplay of growth mode and thermally induced spin accumulation in epitaxial Al/Co${}_2$TiSi/Al and Al/Co${}_2$TiGe/Al contacts
• Spin-caloric transport properties of cobalt nanostructures: spin disorder effects from first principles
• Spin transport and spin-caloric effects in (Cr,Zn)Te half-metallic nanostructures: Effect of spin disorder at elevated temperatures from first principles

Cited by in corpus (14)

• Fundamental difference in the electronic reconstruction of infinite-layer vs. perovskite neodymium nickelate films on SrTiO${}_3$(001)
• Large magneto-Seebeck effect in magnetic tunnel junctions with half-metallic Heusler electrodes
• Design of $n$- and $p$-type oxide thermoelectrics in LaNiO${}_3$/SrTiO${}_3(001)$ superlattices exploiting interface polarity
• Confinement- and strain-induced enhancement of thermoelectric properties in LaNiO${}_3$/LaAlO${}_3(001)$ superlattices
• Correlated interface electron gas in infinite-layer nickelate versus cuprate films on SrTiO${}_3$(001)
• Inducing $n$- and $p$-type thermoelectricity in oxide superlattices by strain tuning of orbital-selective transport resonances
• Native defects in the Co${}_2$Ti$Z$ ($Z=$ Si, Ge, Sn) full Heusler alloys: formation and influence on the thermoelectric properties
• Tunnel magneto-Seebeck effect
• Competition of defect ordering and site disproportionation in strained LaCoO${}_3$ on SrTiO${}_3$(001)
• Enhancement of thermovoltage and tunnel magneto-Seebeck effect in CoFeB based magnetic tunnel junctions by variation of the MgAl${}_2$O${}_4$ and MgO barrier thickness
• Nature of the magnetic coupling in infinite-layer nickelates versus cuprates
• Ab initio simulation of the structure and transport properties of zirconium and ferromagnetic cobalt contacts on the two-dimensional semiconductor WS_2
• Strain-induced enhancement of the Seebeck effect in magnetic tunneling junctions via interface resonant tunneling: Ab-initio study
• IrCrMnZ (Z=Al, Ga, Si, Ge) Heusler alloys as electrode materials for MgO-based magnetic tunneling junctions: A first-principles study