Comparative study of spin-dependent transport in Co₂FeAl/MgAl₂O₄/CoFe magnetic tunnel junctions with and without thin CoFe interface insertion: an elastic and inelastic scattering model analysis

Abstract

We compare structural and transport properties of Co 2 FeAl (CFA)/MgAl 2 O 4 (MAO)/CoFe magnetic tunnel junctions (MTJs) with and without a 1 nm thick CoFe insertion layer. While the two MTJs show a large difference in resistance area (RA) product, there is no significant difference in their stacked structures such as the thickness of an MAO barrier. Temperature (T) dependence of tunneling conductance (G P and G AP for parallel and antiparallel configurations, respectively) was investigated for the two MTJs, as well as their tunnel magnetoresistance that exceeds 200%. The most striking feature of the temperature dependence is that nonmonotonic change appeared by inserting the CoFe layer, i.e. negative dG P /dT emerged only in the CFA/1 nm CoFe/MAO/CoFe MTJ. The observed results of G P and G AP were analyzed in a model proposed by Hu et al (2016 Phys. Rev. B 94, 094428), in which elastic (spin-conserved) and inelastic (spin-flip scattering) terms were considered. We found that the non-monotonic change observed in T dependence of G P is associated with dominance of the elastic tunneling term. This study demonstrated that the model analysis of T dependence of G P can give insight into the microscopic transport mechanism.

Temperature-dependent spin polarization of Heusler Co2MnSi from the disordered local-moment approach: Effects of atomic disordering and nonstoichiometry

“…For the η parameter, here, we ignore a difference between the M = P and AP cases, i.e., η = η P = η AP , since the values fitted from the experiments are same in magnitude, typically ∼10 −5 [31,77]. The fitting analyses are carried out for both total (spd)-and itinerant (sp)-orbital spin polarizations; the fitting curves are plotted with solid lines in Fig.…”

The large perpendicular magnetic anisotropy induced at the Co2FeAl/MgAl2O4 interface and tuned with the strain, voltage and charge doping by first principles study

“…Materials with a smaller band gap generally have lower resistivity and the insulators with low-resistivity help reduce junction resistance, thereby reducing the resistance area (RA) of the MTJ [39]. However, no reduction of RA in MAO barrier junctions was observed in experiments [40][41][42]. The effective PMA of CFA/MAO is about 1.6 mJ m −2 when annealed at 400 °C [27], which is equivalent to that of CFA/ MgO [18].…”

Magnetic properties, adhesive characteristics, and optical properties of Co40Fe40W20films

“…Recent years have seen increased attention being given to adding novel elements into materials in a magnetic field. Research on adding other elements to a CoFe matrix has also increased from recent years [1][2][3][4][5][6][7]. Several studies have investigated adding a third element to the original CoFe material.…”