The Influence of the Ferroelectric and Magnetic Configuration on the Tunnel Current in Double Planar Tunnel Junctions with Ferromagnetic Electrodes and Ferroelectric Barriers

2019 ◽  
Vol 257 (3) ◽  
pp. 1900489
Author(s):  
Michał Wilczyński
Keyword(s):  
Tunnel Junctions ◽  
Magnetic Configuration ◽  
Tunnel Current ◽  
Ferromagnetic Electrodes

Which states contribute to the tunneling current for large barrier thicknesses?

2006 ◽  
Vol 941 ◽  
Author(s):  
Christian Heiliger ◽  
Peter Zahn ◽  
Ingrid Mertig
Keyword(s):  
Ab Initio ◽  
Transport Properties ◽  
Tunnel Junctions ◽  
Tunneling Current ◽  
Interface Structure ◽  
Magnetic Configuration ◽  
Barrier Thickness

ABSTRACTThe transport properties of planar Fe/MgO/Fe tunnel junctions are investigated theoretically by means of ab initio calculations. In particular, the k||-resolved conductance in dependence on the barrier thickness, the interface structure, and the magnetic configuration is studied. The results show that the number of states in the k||-space contributing significantly to the overall current is decreasing with increasing barrier thickness as expected. In contrast to simple parabolic band models the contribution of states in the vicinity of k||=0, however, is only involved for a few considered configurations of the system Fe/MgO/Fe.

Non-Equilibrium Green’s Function Modeling of the Transport Characteristics of Magnetic Tunnel Junctions Containing Anderson Impurities

SPIN ◽  
2020 ◽  
Vol 10 (01) ◽  
pp. 2050006
Author(s):  
Parvathy Harikumar ◽  
S. Mathi Jaya
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Many Body ◽  
Applied Bias ◽  
Tunnel Current ◽  
Spin Polarized ◽  
Barrier Region ◽  
Non Equilibrium Green’S Function

A nonequilibrium Green’s function (NEGF) formulation to study the transport characteristics of magnetic tunnel junctions (MTJs) that contains impurities at the barrier region and many-body interaction at the electrode region is presented. The formulation makes use of the already developed NEGF method for MTJs without any impurities and the impurity Green’s function is obtained using Haldane’s approach that explicitly takes into account the on-site Coulomb interaction ([Formula: see text]) of the impurity. The formulation is used to obtain the spin-dependent tunnel current of model MTJs as a function of the applied bias for different values of [Formula: see text] corresponding to both the parallel and antiparallel configuration of the end electrodes of the MTJ. The tunnel currents are used to obtain the tunnel magnetoresistance (TMR) of the MTJ and we observed from our study that the TMR is strongly influenced by the impurities. The TMR is found to be reduced compared to that of the MTJ without impurities and the bias dependence of the TMR is found to be strongly influenced by [Formula: see text]. Our studies revealed that the MTJ can exhibit almost completely spin polarized current at certain values of [Formula: see text].

Tunnel Junctions With Yttrium Oxide Barrier and Various Ferromagnetic Electrodes

2004 ◽  
Vol 40 (4) ◽  
pp. 2296-2298 ◽  
Author(s):  
T. Dimopoulos ◽  
G. Gieres ◽  
S. Colis ◽  
R. Lopez ◽  
M. Vieth ◽  
...  
Keyword(s):  
Yttrium Oxide ◽  
Tunnel Junctions ◽  
Ferromagnetic Electrodes ◽  
Oxide Barrier

Fabrication of high-magnetoresistance tunnel junctions using Co75Fe25 ferromagnetic electrodes

2000 ◽  
Vol 77 (2) ◽  
pp. 283-285 ◽  
Author(s):  
Xiu-Feng Han ◽  
Mikihiko Oogane ◽  
Hitoshi Kubota ◽  
Yasuo Ando ◽  
Terunobu Miyazaki
Keyword(s):  
Tunnel Junctions ◽  
Ferromagnetic Electrodes

Spin-Polarized Current in Spin Valves and Magnetic Tunnel Junctions

MRS Bulletin ◽  
2006 ◽  
Vol 31 (5) ◽  
pp. 389-394 ◽  
Author(s):  
Stuart Parkin
Keyword(s):  
Room Temperature ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Memory Storage ◽  
Tunnel Barrier ◽  
Tunnel Magnetoresistance ◽  
Ferromagnetic Electrodes ◽  
Diffusive Scattering ◽  
Spin Polarized ◽  
Tunnel Barriers

AbstractSpin-polarized currents can be generated by spin-dependent diffusive scattering in magnetic thin-film structures or by spin-dependent tunneling across ultrathin dielectrics sandwiched between magnetic electrodes.By manipulating the magnetic moments of the magnetic components of these spintronic materials, their resistance can be significantly changed, allowing the development of highly sensitive magnetic-field detectors or advanced magnetic memory storage elements.Whereas the magneto-resistance of useful devices based on spin-dependent diffusive scattering has hardly changed since its discovery nearly two decades ago, in the past five years there has been a remarkably rapid development in both the basic understanding of spin-dependent tunneling and the magnitude of useful tunnel magnetoresistance values.In particular, it is now evident that the magnitude of the spin polarization of tunneling currents in magnetic tunnel junctions not only is related to the spin-dependent electronic structure of the ferromagnetic electrodes but also is considerably influenced by the properties of the tunnel barrier and its interfaces with the magnetic electrodes.Whereas the maximum tunnel magnetoresistance of devices using amorphous alumina tunnel barriers and 3d transition-metal alloy ferromagnetic electrodes is about 70% at room temperature, using crystalline MgO tunnel barriers in otherwise the same structures gives tunnel magnetoresistance values of more than 350% at room temperature.

Complex magnetic response in magnetic tunnel junctions determined via magnetic and transport measurements

2002 ◽  
Vol 746 ◽  
Author(s):  
R. Guerrero ◽  
V. V. Pryadun ◽  
F. G. Aliev ◽  
R. Villar ◽  
J. L. Martinez ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Tunnel Junctions ◽  
Ac Susceptibility ◽  
Low Frequency ◽  
Magnetic Tunnel Junctions ◽  
Magnetic Response ◽  
Magnetization Dynamics ◽  
Dc Magnetization ◽  
Ferromagnetic Electrodes ◽  
Ac Magnetization

We have studied the low frequency complex magnetization dynamics in Co/Al2O3/Ni80Fe20 magnetic tunnel junctions (MTJs) at temperatures between 4.2K and 300K. The measurements were carried out by using two different experimental techniques. The first method probes directly magnetic properties via DC magnetization and AC susceptibility, while the second one measures AC magnetization dynamics of the ferromagnetic electrodes near the cross area, which is related to the tunnelling resistance.

SOME PHONON EFFECTS IN SUPERCONDUCTING TUNNEL JUNCTIONS

1965 ◽  
Vol 43 (4) ◽  
pp. 557-562 ◽  
Author(s):  
J. G. Adler ◽  
J. S. Rogers ◽  
S. B. Woods
Keyword(s):  
Temperature Dependence ◽  
Phonon Spectrum ◽  
Energy Gap ◽  
Tunnel Junctions ◽  
Phonon Energy ◽  
Superconducting Tunnel Junctions ◽  
Tunnel Current ◽  
Broad Group ◽  
Superconducting Energy Gap ◽  
Phonon Structure

Tunneling measurements have been made on junctions consisting of aluminium separated from a second metal by aluminium oxide insulating layers. When the second metal was lead, tin, or indium, the effect of its phonon spectrum on the tunnel current was observed. Results with indium indicate that there is a broad group of phonons at an energy of 5 millivolts and another group at an energy of 13 millivolts in the indium phonon spectrum. The end point of the spectrum is at 14.8 ± 0.1 millivolts. Evidence is presented for a relationship between the strength of the phonon structure, the phonon energy, and the width of the superconducting energy gap from measurements on lead, tin, and indium. Measurements of the temperature dependence of the phonon structure in lead and indium are also reported.

scholarly journals Spin filtering by proximity effects at hybridized interfaces in spin-valves with 2D graphene barriers

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Maëlis Piquemal-Banci ◽  
Regina Galceran ◽  
Simon M.-M. Dubois ◽  
Victor Zatko ◽  
Marta Galbiati ◽  
...  
Keyword(s):  
Spin Transport ◽  
Tunnel Junctions ◽  
State Of The Art ◽  
Proximity Effects ◽  
Monolayer Graphene ◽  
Ferromagnetic Electrodes ◽  
Number Of Layers ◽  
Strength Of Interaction ◽  
Spin Properties ◽  
Magneto Resistance

Abstract We report on spin transport in state-of-the-art epitaxial monolayer graphene based 2D-magnetic tunnel junctions (2D-MTJs). In our measurements, supported by ab-initio calculations, the strength of interaction between ferromagnetic electrodes and graphene monolayers is shown to fundamentally control the resulting spin signal. In particular, by switching the graphene/ferromagnet interaction, spin transport reveals magneto-resistance signal MR > 80% in junctions with low resistance × area products. Descriptions based only on a simple K-point filtering picture (i.e. MR increase with the number of layers) are not sufficient to predict the behavior of our devices. We emphasize that hybridization effects need to be taken into account to fully grasp the spin properties (such as spin dependent density of states) when 2D materials are used as ultimately thin interfaces. While this is only a first demonstration, we thus introduce the fruitful potential of spin manipulation by proximity effect at the hybridized 2D material / ferromagnet interface for 2D-MTJs.

Sign in / Sign up

Export Citation Format

Share Document