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Spinel MgAl2O4 and family oxides are emerging barrier materials useful for magnetic tunnel junctions (MTJs). We report large tunnel magnetoresistance (TMR) ratios up to 429% at room temperature (RT) and 1,034% at 10 K in a…

Materials Science · Physics 2022-02-02 Thomas Scheike , Zhenchao Wen , Hiroaki Sukegawa , Seiji Mitani

We present a study of the tunnel magneto-Seebeck (TMS) effect in MgO based magnetic tunnel junctions (MTJs). The electrodes consist of CoFeB with in-plane magnetic anisotropy. The temperature gradients which generate a voltage across the…

Spin-polarized tunneling in FMS/M/FMS double tunnel junctions where FMSs are ferromagnetic semiconductor layers and M is a metal spacer is studied theoretically within the single-site coherent potential approximation (CPA). The exchange…

Disordered Systems and Neural Networks · Physics 2009-11-07 Alireza Saffarzadeh

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…

Materials Science · Physics 2018-05-16 Benjamin Geisler , Peter Kratzer

We report on room temperature low frequency noise due to magnetic inhomogeneities/domain walls (MI/DWs) in elliptic submicron FeCoB/MgO/FeCoB magnetic tunnel junctions with an area between 0.0245 and 0.0675{\mu}m2. In the smaller area…

Mesoscale and Nanoscale Physics · Physics 2012-04-18 D. Herranz , A. Gomez-Ibarlucea , M. Schäfers , A. Lara , G. Reiss , F. G. Aliev

Magnetotransport properties are investigated for a high mobility Si two dimensional electron systems in the vicinity of a Landau level crossing point. At low temperatures, the resistance peak having a strong anisotropy shows large…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Kiyohiko Toyama , Takahisa Nishioka , Kentarou Sawano , Yasuhiro Shiraki , Tohru Okamoto

We report tunnel magnetoresistance (TMR) ratios as high as 472% at room temperature and 804% at 5 K in pseudo-spin valve (SV) CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) annealed at 450oC, which is approaching the theoretically…

Materials Science · Physics 2009-11-11 Jun Hayakawa , Shoji Ikeda , Young Min Lee , Fumihiro Matsukura , Hideo Ohno

Perpendicularly magnetized CoFeB layers with ultra-thin non-magnetic insertion layers are very widely used as the electrodes in magnetic tunnel junctions for spin transfer magnetic random access memory devices. Exchange interactions play a…

Mesoscale and Nanoscale Physics · Physics 2019-10-25 Jamileh Beik Mohammadi , Bartek Kardasz , Georg Wolf , Yizhang Chen , Mustafa Pinarbasi , Andrew D. Kent

The layers of a high-temperature novel GaAs:Fe diluted magnetic semiconductor (DMS) with an average Fe content up to 20 at. % were grown on (001) i-GaAs substrates using a pulsed laser deposition in a vacuum. The transmission electron…

We investigate bias voltage effects on the spin-dependent transport properties of Fe/MgAl${}_2$O${}_4$/Fe(001) magnetic tunneling junctions (MTJs) by comparing them with those of Fe/MgO/Fe(001) MTJs. By means of the nonequilibrium Green's…

Materials Science · Physics 2017-08-23 Keisuke Masuda , Yoshio Miura

We present evidence of direct electron tunneling across intrinsic insulating regions in sub-micrometer wide bridges of the phase separated ferromagnet (La,Pr,Ca)MnO$_3$. Upon cooling below the Curie temperature, a predominantly…

Strongly Correlated Electrons · Physics 2015-08-10 G. Singh-Bhalla , S. Selcuk , T. Dhakal , A. Biswas , A. F. Hebard

The escape of a small current-biased Josephson tunnel junction from the zero voltage state in the presence of weak microwave radiation is investigated experimentally at low temperatures. The measurements of the junction switching current…

Superconductivity · Physics 2009-11-07 A. Wallraff , T. Duty , A. Lukashenko , A. V. Ustinov

We present measurements of magnetic tunnel junctions made using a self-assembled-monolayer molecular barrier. Ni/octanethiol/Ni samples were fabricated in a nanopore geometry. The devices exhibit significant changes in resistance as the…

Mesoscale and Nanoscale Physics · Physics 2010-10-05 J. R. Petta , S. K. Slater , D. C. Ralph

In quasi-magnetic tunnel junctions (QMTJs) with a EuS spin filter tunnel barrier between Al and Co electrodes, we observed large magnetoresistance (MR). The bias dependence shows an abrupt increase of MR ratio in high bias voltage, which is…

Materials Science · Physics 2009-11-13 T. Nagahama , T. S. Santos , J. S. Moodera

We have studied the magnetotransport properties of a high mobility two-dimensional hole gas (2DHG) system in a 10nm GaAs quantum well (QW) with densities in range of 0.7-1.6*10^10 cm^-2 on the metallic side of the zero-field…

Strongly Correlated Electrons · Physics 2009-11-07 Xuan P. A. Gao , Allen P. Mills , Arthur P. Ramirez , Loren N. Pfeiffer , Kenneth W. West

Exchange bias phenomenon is generally ascribed to the exchange coupling at the interfaces between ferromagnetic and antiferromagnetic layers. Here, we propose a bulk form of exchange bias in a single-phase magnet where the coupling between…

Strongly Correlated Electrons · Physics 2013-06-07 Young Sun , Junzhuang Cong , Yisheng Chai , Liqin Yan , Yuelei Zhao , Shouguo Wang , Wei Ning , Yuheng Zhang

High quality epitaxial NbN/MgO/NbN Josephson junctions have been realized with MgO barriers up to a thickness of d=1 nm. The junction properties coherently scale with the size of barrier, and low critical current densities down to 3…

We suggest a model of synthetic ferrimagnetic semiconductor structure based on GaAs-AlGaAs quantum well doped by two Mn delta-layers. The coupling between the delta-layers is mediated by extra holes, and can be switched between ferro- and…

Strongly Correlated Electrons · Physics 2020-03-19 N. V. Agrinskaya , A. M. Kalashnikova , V. I. Kozub

Temperature- and bias voltage-dependent transport measurements of magnetic tunnel junctions (MTJs) with perpendicularly magnetized Co/Pd electrodes are presented. Magnetization measurements of the Co/Pd multilayers are performed to…

Materials Science · Physics 2015-05-19 Zoë Kugler , Volker Drewello , Markus Schäfers , Jan Schmalhorst , Günter Reiss , Andy Thomas

The conditions for the occurrence of pronounced magnetoelectric bistabilities in the resonant tunneling through a ferromagnetic quantum well are theoretically investigated. The bistability appears due to the mutual feedback of the carriers…

Other Condensed Matter · Physics 2008-10-22 Christian Ertler