Large magneto-Seebeck effect in magnetic tunnel junctions with half-metallic Heusler electrodes

Abstract

Spin caloritronics studies the interplay between charge-, heat- and spin-currents, which are initiated by temperature gradients in magnetic nanostructures. A plethora of new phenomena has been discovered that promises, e.g., to make wasted heat in electronic devices useable or to provide new read-out mechanisms for information. However, only few materials have been studied so far with Seebeck voltages of only some μV, which hampers applications. Here, we demonstrate that half-metallic Heusler compounds are hot candidates for enhancing spin-dependent thermoelectric effects. This becomes evident when considering the asymmetry of the spin-split density of electronic states around the Fermi level that determines the spin-dependent thermoelectric transport in magnetic tunnel junctions. We identify Co${}_2$FeAl and Co${}_2$FeSi Heusler compounds as ideal due to their energy gaps in the minority density of states, and demonstrate devices with substantially larger Seebeck voltages and tunnel magneto-Seebeck effect ratios than the commonly used Co-Fe-B based junctions.

arXiv comment9 pages, 4 figures

References in corpus (21)

• Spin Caloritronics
• Calculated electronic and magnetic properties of the half-metallic, transition metal based Heusler compounds
• Seebeck Effect in Magnetic Tunnel Junctions
• Tunneling magneto thermo power in magnetic tunnel junction nanopillars
• Spin caloritronics in magnetic tunnel junctions: Ab initio studies
• Seebeck coefficients of half-metallic ferromagnets
• Giant thermal spin torque assisted magnetic tunnel junction switching
• Thermal transport and non-equilibrium temperature drop across a magnetic nanostructured interface
• Time-resolved measurement of the tunnel magneto-Seebeck effect in a single magnetic tunnel junction
• Determination of spin-dependent Seebeck coefficients of CoFeB/MgO/CoFeB magnetic tunnel junction nanopillars
• GW study of the half-metallic Heusler compounds Co2MnSi and Co2FeSi
• Low Gilbert damping in Co2FeSi and Fe2CoSi films
• Parameter space for thermal spin-transfer torque
• Comparison of laser induced and intrinsic tunnel magneto-Seebeck effect in CoFeB/MgAl${}_2$O${}_4$ and CoFeB/MgO magnetic tunnel junctions
• Spincaloric properties of epitaxial Co${}_2$MnSi/MgO/Co${}_2$MnSi magnetic tunnel junctions
• Comparison of the magneto-Peltier and magneto-Seebeck effects in magnetic tunnel junctions
• Ab initio studies of the tunneling magneto-Seebeck effect: influence of magnetic material
• Insights into the electronic structure of Co2FeSi from x-ray magnetic linear dichroism
• High TMR ratio in Co2FeSi and Fe2CoSi based magnetic tunnel junctions
• On/off switching of bit readout in bias-enhanced tunnel magneto-Seebeck effect
• Titanium Nitride as a Seed Layer for Heusler Compounds

Cited by in corpus (7)

• Large anomalous Nernst effect in thin films of the Weyl semimetal Co2MnGa
• Tunnel magneto-Seebeck effect
• Spin-driven electrical power generation at room temperature
• 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
• Anomalous Nernst effect on the nanometer scale: Exploring three-dimensional temperature gradients in magnetic tunnel junctions
• Thermal conductivity of thin insulating films determined by tunnel magneto-Seebeck effect measurements and finite-element modeling
• Strain-induced enhancement of the Seebeck effect in magnetic tunneling junctions via interface resonant tunneling: Ab-initio study