Effect of Hybridization on Exchange Coupling in Magnetic Multilayers

ABSTRACTAn earlier theory of the exchange coupling between two ferromagnets separated by a nonmagnetic transition metal spacer was based on size quantization of the electron energies in the spacer. It is now generalized to include the effect of hybridization between the conduction and d bands both in the ferromagnet and in the spacer. The new theory thus unifies the approach based on coupling via d electrons, valid for transition metal spacers, with RKKY-type theories for noble and simple metals which rely on coupling via conduction electrons. The theory is applied to calculate the period and strength of the long-period oscillatory coupling in (001) CO/Cu trilayer.

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SEMPA Studies of Exchange Coupling in Magnetic Multilayers

MRS Bulletin ◽

10.1557/s0883769400045310 ◽

1995 ◽

Vol 20 (10) ◽

pp. 30-33 ◽

Cited By ~ 6

Author(s):

R.J. Celotta ◽

D.T. Pierce ◽

J. Unguris

Keyword(s):

Magnetic Field ◽

Exchange Coupling ◽

Giant Magnetoresistance ◽

Large Change ◽

Magnetic Multilayers ◽

Information Storage ◽

Conduction Electrons ◽

Spacer Layer ◽

Ferromagnetic Layers ◽

Oscillatory Coupling

In the late 1980s, a number of exciting yet puzzling observations resulted from experiments investigating the coupling between two ferromagnetic layers separated by a nonferromagnetic spacer layer. A pioneering experiment by Grünberg et al. showed that Fe layers separated by a thin Cr spacer aligned with antiparallel magnetization, but with Au as the spacer layer, a parallel alignment occurred. The long-range magnetic dipole from each layer would tend to explain antiparallel alignment; small pinholes in the spacer layer would produce parallel alignment. Alternatively, the layers might be coupled through the spacer-layer conduction electrons by the Ruder man-Kittel-Kasuya-Yosida (RKKY) effect. This was expected to produce an oscillation in coupling as the spacer thickness increased, that is, an oscillation between parallel and antiparallel alignment. Oscillatory coupling was first observed by Parkin et al. Researchers had also found that, at spacer thicknesses where antiparallel alignment occurred, the Fe/Cr/Fe system can exhibit a giant magnetoresistance (GMR) effect, that is, an anomalously large change in resistance when a magnetic field is applied. The potential technological importance of the GMR effect to magnetic sensing and magnetic information storage added further impetus to the already rapidly growing area of research in magnetic multilayers.

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Mechanism of the Exchange Coupling in Transition Metal Magnetic Multilayers

EPL (Europhysics Letters) ◽

10.1209/0295-5075/30/3/009 ◽

1995 ◽

Vol 30 (3) ◽

pp. 175-180 ◽

Cited By ~ 1

Author(s):

E. M Chudnovsky

Keyword(s):

Transition Metal ◽

Exchange Coupling ◽

Magnetic Multilayers

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Simple theory of exchange coupling in transition-metal magnetic multilayers

Physical Review B ◽

10.1103/physrevb.44.5977 ◽

1991 ◽

Vol 44 (11) ◽

pp. 5977-5980 ◽

Cited By ~ 70

Author(s):

D. M. Deaven ◽

D. S. Rokhsar ◽

M. Johnson

Keyword(s):

Transition Metal ◽

Exchange Coupling ◽

Magnetic Multilayers ◽

Simple Theory

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Long and Short Range Oscillatory Exchange Coupling in Fe/Cu and Co/Cu Magnetic Multilayers

MRS Proceedings ◽

10.1557/proc-231-195 ◽

1991 ◽

Vol 231 ◽

Cited By ~ 17

Author(s):

F. Herman ◽

J. Sticht ◽

M. Van Schilfgaarde

Keyword(s):

Long Range ◽

First Principles ◽

Exchange Coupling ◽

Short Range ◽

Physical Mechanism ◽

Magnetic Multilayers ◽

Electronic Transitions ◽

Fermi Sphere ◽

Spacer Thickness ◽

Oscillatory Coupling

AbstractBy carrying out accurate first-principles superlattice calculations, we determined the exchange coupling in bcc Fe/Cu and fcc Co/Cu multilayers as a function of the Cu spacer thickness. The fact that we can obtain long-range oscillatory coupling directly from first principles suggests that our theoretical model includes the underlying physical mechanism, and that such coupling is indeed a band structure effect. The exchange coupling depends on the interfacial orientation as well as on the Cu spacer thickness. In bcc [001] Fe/Cu, fcc [001] Co/Cu, and fcc [110] Co/Cu, the coupling has both long and short-range oscillatory components, while in fcc [111] Co/Cu, the long-range component dominates. Using a simplified model for the Fermi surface of the Cu spacer, we can relate the short-range oscillations to electronic transitions across the Fermi sphere, and the long-range oscillations to electronic transitions between spheres in adjacent zones in extended k-space, i.e., to interzonal transitions.

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Exchange Coupling of Transition-Metal Ions through Hydrogen Bonding: A Theoretical Investigation

Journal of the American Chemical Society ◽

10.1021/ja0178160 ◽

2002 ◽

Vol 124 (18) ◽

pp. 5197-5205 ◽

Cited By ~ 154

Author(s):

Cédric Desplanches ◽

Eliseo Ruiz ◽

Antonio Rodríguez-Fortea ◽

Santiago Alvarez

Keyword(s):

Hydrogen Bonding ◽

Transition Metal ◽

Metal Ions ◽

Theoretical Investigation ◽

Exchange Coupling ◽

Transition Metal Ions

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Ruderman–Kittel–Kasuya–Yosida-type interfacial Dzyaloshinskii–Moriya interaction in heavy metal/ferromagnet heterostructures

Nature Communications ◽

10.1038/s41467-021-23586-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Taehyun Kim ◽

In Ho Cha ◽

Yong Jin Kim ◽

Gyu Won Kim ◽

Andrey Stashkevich ◽

...

Keyword(s):

Heavy Metal ◽

Exchange Coupling ◽

Spin Orbit Coupling ◽

Conduction Electrons ◽

Indirect Exchange ◽

Metal Atoms ◽

Technological Potential ◽

Interfacial Modification ◽

Coupling Phenomena ◽

Moriya Interaction

AbstractThe manipulation of magnetization with interfacial modification using various spin-orbit coupling phenomena has been recently revisited due to its scientific and technological potential for next-generation memory devices. Herein, we experimentally and theoretically demonstrate the interfacial Dzyaloshinskii–Moriya interaction characteristics penetrating through a MgO dielectric layer inserted between the Pt and CoFeSiB. The inserted MgO layer seems to function as a chiral exchange interaction mediator of the interfacial Dzyaloshinskii–Moriya interaction from the heavy metal atoms to ferromagnet ones. The potential physical mechanism of the anti-symmetric exchange is based on the tunneling-like behavior of conduction electrons through the semi-conductor-like ultrathin MgO. Such behavior can be correlated with the oscillations of the indirect exchange coupling of the Ruderman–Kittel–Kasuya–Yosida type. From the theoretical demonstration, we could provide approximate estimation and show qualitative trends peculiar to the system under investigation.

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