Two interface effects: Exchange bias and magnetic proximity

Manna, P. K.; Yusuf, S. M.

doi:10.1016/j.physrep.2013.10.002

“…3. Therefore the AFM coupling is a remarkable example of the magnetic proximity effect [27]. At larger fields the Gd signal is dominated by the paramagnetic contribution of Gd atoms which are not exchange-coupled to the Co clusters.…”

Section: B Below the Coalescence Thresholdmentioning

confidence: 99%

Magnetism and morphology of Co nanocluster superlattices onGdAu2/Au(111)–(13×13)

Cavallin

¹

,

Fernández

²

,

Ilyn³

et al. 2014

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We present a comprehensive study of the magnetism and morphology of an ultrahigh density array of Co nanoclusters self-assembled on the single atomic layer GdAu 2 on Au(111) template surface. Combining scanning tunneling microscopy, x-ray magnetic circular dichroism, and magneto-optical Kerr effect measurements, we reveal a significant enhancement of the perpendicular magnetic anisotropy energy for noncoalesced single atomic layer nanoclusters compared to Co/Au(111). For coverages well beyond the onset of coalescence, we observe room-temperature in-plane magnetic remanence.

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“…An interesting class of nanoparticles (NP) is found when ferromagnetic (FM) and antiferromagnetic (AF) materials are combined together in a core/shell structure. The coupling at the interface between these two magnetic phases gives rise to the EB phenomenon [6][7][8][9][10], which is of fundamental interest and has found multiple technological applications depending on the specific composition and the characteristic size of the respective phases [11][12][13][14][15][16]. The pinning mechanism, that results from EB, has been commercially explored for magnetic field sensors and in modern magnetic read heads [17,18].…”

Section: Introductionmentioning

confidence: 99%

Probing core and shell contributions to exchange bias in Co/Co<inf>3</inf>O<inf>4</inf> nanoparticles of controlled size

De¹,

Iglesias

²

,

Majumdar

³

et al. 2017

2017 IEEE International Magnetics Conference (INTERMAG)

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Coupling at the interface of core/shell magnetic nanoparticles is known to be responsible for exchange bias (EB) and the relative sizes of core and shell components are supposed to influence the associated phenomenology. In this work, we have prepared core/shell structured nanoparticles with a total average diameter around ∼27 nm and a wide range of shell thicknesses through the controlled oxidation of Co nanoparticles well dispersed in an amorphous silica host. Structural characterizations give compelling evidence of the formation of Co 3 O 4 crystallite phase at the shells surrounding the Co core. Field cooled hysteresis loops display nonmonotonous dependence of the exchange bias H E and coercive H C fields, that become maximum for a sample with an intermediate shell thickness, at which lattice strain is also maximum for both phases. The EB effects persist up to temperatures above the ordering temperature of the oxide shell. Results of our atomistic Monte Carlo simulations of particles with the same size and composition as in experiments are in agreement with the experimental observations and have allowed us to identify a change in the contribution of the interfacial surface spins to the magnetization reversal, giving rise to the observed maximum in H E and H C .

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“…An interesting class of nanoparticles (NP) is found when ferromagnetic (FM) and antiferromagnetic (AF) materials are combined together in a core/shell structure. The coupling at the interface between these two magnetic phases gives rise to the EB phenomenon [6][7][8][9][10], which is of fundamental interest and has found multiple technological applications depending on the specific composition and the characteristic size of the respective phases [11][12][13][14][15][16]. The pinning mechanism, that results from EB, has been commercially explored for magnetic field sensors and in modern magnetic read heads [17,18].…”

Section: Introductionmentioning

confidence: 99%

Probing core and shell contributions to exchange bias inCo/Co3O4nanoparticles of controlled size

De

¹

,

Iglesias

²

,

Majumdar

³

et al. 2016

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Coupling at the interface of core/shell magnetic nanoparticles is known to be responsible for exchange bias (EB) and the relative sizes of core and shell components are supposed to influence the associated phenomenology. In this work, we have prepared core/shell structured nanoparticles with a total average diameter around ∼27 nm and a wide range of shell thicknesses through the controlled oxidation of Co nanoparticles well dispersed in an amorphous silica host. Structural characterizations give compelling evidence of the formation of Co 3 O 4 crystallite phase at the shells surrounding the Co core. Field cooled hysteresis loops display nonmonotonous dependence of the exchange bias H E and coercive H C fields, that become maximum for a sample with an intermediate shell thickness, at which lattice strain is also maximum for both phases. The EB effects persist up to temperatures above the ordering temperature of the oxide shell. Results of our atomistic Monte Carlo simulations of particles with the same size and composition as in experiments are in agreement with the experimental observations and have allowed us to identify a change in the contribution of the interfacial surface spins to the magnetization reversal, giving rise to the observed maximum in H E and H C .

show abstract

Two interface effects: Exchange bias and magnetic proximity

Cited by 248 publications

References 298 publications

Magnetism and morphology of Co nanocluster superlattices onGdAu2/Au(111)–(13×13)

Magnetism and morphology of Co nanocluster superlattices onGdAu2/Au(111)–(13×13)

Probing core and shell contributions to exchange bias in Co/Co<inf>3</inf>O<inf>4</inf> nanoparticles of controlled size

Probing core and shell contributions to exchange bias inCo/Co3O4nanoparticles of controlled size

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