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Full-Text Articles in Physics
Atomic And Electronic Structure Of Cofeb/Mgo Interface From First Principles, John D. Burton, Sitaram S. Jaswal, Evgeny Y. Tsymbal, O. G. Heinonen
Atomic And Electronic Structure Of Cofeb/Mgo Interface From First Principles, John D. Burton, Sitaram S. Jaswal, Evgeny Y. Tsymbal, O. G. Heinonen
Evgeny Tsymbal Publications
First-principles calculations of the atomic and electronic structure of crystalline CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) are performed to understand the effect of B on spin-dependent transport in these junctions. The authors find that it is energetically favorable for B atoms to reside at the crystalline CoFeB/MgO interface rather than remain in the bulk of the crystalline CoFeB electrode. The presence of B at the interfaces is detrimental to tunneling magnetoresistance (TMR) because it significantly suppresses the majority-channel conductance through states of symmetry. Preventing B segregation to the interfaces during annealing should result in an enhanced TMR in CoFeB/MgO/CoFeB MTJs.
Interlayer Exchange Coupling In Fe/Mgo/Fe Magnetic Tunnel Junctions, T. Katayama, S. Yuasa, Julian P. Velev, M. Ye. Zhuravlev, Sitaram S. Jaswal, Evgeny Y. Tsymbal
Interlayer Exchange Coupling In Fe/Mgo/Fe Magnetic Tunnel Junctions, T. Katayama, S. Yuasa, Julian P. Velev, M. Ye. Zhuravlev, Sitaram S. Jaswal, Evgeny Y. Tsymbal
Evgeny Tsymbal Publications
Interlayer exchange coupling (IEC) in fully epitaxial Fe/MgO/Fe (001) tunnel junctions with wedge-shaped MgO layers is measured at room temperature from the unidirectional shift of the Kerr hysteresis loop. It is found that the IEC is antiferromagnetic for small MgO thickness but changes sign at 0.8 nm. Ab initio calculations of IEC show that this behavior can be explained by the presence of O vacancies in the MgO barrier which makes IEC antiferromagnetic for thin barriers. With increasing MgO thickness the resonance contribution to IEC from localized defect states is reduced resulting in the ferromagnetic coupling typical for perfect MgO …
Magnetic Moment Softening And Domain Wall Resistance In Ni Nanowires, John D. Burton, Renat F. Sabirianov, Sitaram S. Jaswal, Evgeny Y. Tsymbal, O. N. Mryasov
Magnetic Moment Softening And Domain Wall Resistance In Ni Nanowires, John D. Burton, Renat F. Sabirianov, Sitaram S. Jaswal, Evgeny Y. Tsymbal, O. N. Mryasov
Evgeny Tsymbal Publications
We perform ab initio calculations of the electronic structure and conductance of atomic-size Ni nanowires with domain walls only a few atomic lattice constants wide. We show that the hybridization between noncollinear spin states leads to a reduction of the magnetic moments in the domain wall resulting in the enhancement of the domain wall resistance. Experimental studies of the magnetic moment softening may be feasible with modern techniques such as scanning tunneling spectroscopy.
Predicted Magnetoelectric Effect In Fe/Batio3 Multilayers: Ferroelectric Control Of Magnetism, Chun-Gang Duan, Sitaram S. Jaswal, Evgeny Y. Tsymbal
Predicted Magnetoelectric Effect In Fe/Batio3 Multilayers: Ferroelectric Control Of Magnetism, Chun-Gang Duan, Sitaram S. Jaswal, Evgeny Y. Tsymbal
Evgeny Tsymbal Publications
An unexplored physical mechanism which produces a magnetoelectric effect in ferroelectricferromagnetic multilayers is studied based on first-principles calculations. Its origin is a change in bonding at the ferroelectric-ferromagnet interface that alters the interface magnetization when the electric polarization reverses. Using Fe/BaTiO3 multilayers as a representative model, we show a sizable difference in magnetic moments of Fe and Ti atoms at the two interfaces dissimilar by the orientation of the local electric dipole moments. The predicted magnetoelectric effect opens a new direction to control magnetic properties of thin-film layered structures by electric fields.
Tunneling Across A Ferroelectric, Evgeny Y. Tsymbal, Hermann Kohlstedt
Tunneling Across A Ferroelectric, Evgeny Y. Tsymbal, Hermann Kohlstedt
Evgeny Tsymbal Publications
Spontaneously polarized materials through which electrons pass by tunneling may be used in novel electronic devices and may reveal new basic physics at the nanometer scale.