The influence of finite size and shape anisotropy on exchange bias: A study of patterned Co/CoO nanostructures

Temst, Kristiaan; Popova, E.; Loosvelt, H.; Bael, M. J. Van; Brems, Steven; Bruynseraede, Y.; Haesendonck, Chris Van; Fritzsche, H.; Gierlings, M.; Leunissen, L.H.A.; Jonckheere, R.

doi:10.1016/j.jmmm.2006.02.009

Cited by 11 publications

(6 citation statements)

References 23 publications

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“…Later on, also X-ray photoemission microscopy has been used in Fe/MnPd films, 154 timeresolved Kerr magnetometry in FeF 2 /Fe bilayers 155 neutron scattering in patterned Co/CoO nanostructures. 156 Recently, the origin of asymmetric loops in some particular systems has been ascribed to the competition between the FM and the interfacial FM-AFM exchange anisotropies 157 158 and different reversal processes in both loop branches have also been revealed by SXRMS and techniques in perpendicularly coupled exchange coupled films 159 and by MOKE in Fe/MnF 2 bilayers. 160 Asymmetries in the shape of the hysteresis loops of core/shell particles are also evident in some systems, but, in this case, present experimental techniques cannot easily give information about the microscopic mechanisms involved in the reversal processes because of the particle size dispersion always present in samples.…”

Section: Asymmetry Of the Hysteresis Loopmentioning

confidence: 99%

Exchange Bias Phenomenology and Models of Core/Shell Nanoparticles

Iglesias¹,

Labarta²,

Batlle³

2007

ChemInform

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Some of the main experimental observations related to the occurrence of exchange bias in magnetic systems are reviewed, focusing the attention on the peculiar phenomenology associated to nanoparticles with core/shell structure as compared to thin film bilayers. The main open questions posed by the experimental observations are presented and contrasted to existing theories and models for exchange bias formulated up to date. We also present results of simulations based on a simple model of a core/shell nanoparticle in which the values of microscopic parameters such as anisotropy and exchange constants can be tuned in the core, shell and at the interfacial regions, offering new insight on the microscopic origin of the experimental phenomenology. A detailed study of the magnetic order of the interfacial spins shows compelling evidence that most of the experimentally observed effects can be qualitatively accounted within the context of this model and allows also to quantify the magnitude of the loop shifts in striking agreement with the macroscopic observed values.

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Section: Asymmetry Of the Hysteresis Loopmentioning

confidence: 99%

Exchange Bias Phenomenology and Models of Core/Shell Nanoparticles

Iglesias¹,

Labarta²,

Batlle³

2007

ChemInform

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“…Additionally, a small kink at low fields can be observed. Such a kink has been observed before in different Co/CoO nanostructures [3,2,4]. It has been proposed that thin polycrystalline Co/CoO nanostructures consist of a Co/CoO exchange bias system where the ferromagnetic spins are pinned to the antiferromagnetic domains, as well as a purely ferromagnetic cobalt layer that is free to switch magnetization independently, therefore leading to a small kink at low reversal fields.…”

Section: Resultsmentioning

confidence: 54%

“…Tailoring the magnetic anisotropies of a nanoscale system by means of nanostructuring is an interesting way of manipulating its magnetic properties such as coercivity and exchange bias (EB) [1,2,3,4,5,6,7]. In a thin-film system, several contributions to the overall anisotropy exist, all with different strength, leading to a complex and tunable phase diagram of the magnetic switching behavior.…”

Section: Introductionmentioning

confidence: 99%

Magnetic characterization of oblique angle deposited Co/CoO on gold nanoparticles

Jochum,

Saerbeck,

Lazenka

et al. 2022

Preprint

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The influence of a patterned substrate on obliquely deposited, exchange biased Co/CoO films was studied. It was found that substrates decorated with nanoparticle patterns provide the option to manipulate the orientation of the magnetic easy axis in obliquely deposited thin films. The complementary methods of SQUID magnetometry and polarized neutron reflectometry were used to disentangle the different contributions to the magnetic hysteresis of such complex magnetic systems.

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“…Layered structures of 2D FM and AFM thin films hold a prominent position in the field of spintronic applications based on exchange bias. These layered 2D magnetic thin films provide relatively large-area controllability and easy-tuning of their geometry (dot, 129,130 ring, 131 stripe, 132,133 and wire 134 ), which can be fabricated using various patterning processes including photolithography, 53 and electron beam lithography 130,131 for micro/nano-fabrication. Moreover, the sequential deposition of FM/AFM layers enables the adjustment of surface roughness, [135][136][137] layer thickness, [138][139][140][141][142] and interfacial lattice by regulating the crystallinity of each magnetic thin-film layer.…”

Section: Layered Magnetic Nanomaterials and Exchange Anisotropymentioning

confidence: 99%

“…151 As mentioned previously, conventional deposition and patterning processes are highly suitable for manufacturing layered structures in 2D magnetic thin films. This compatibility of fabrication allows for the customizing of shape and size, ranging from the submicron 129,130,132 to the nanometer scale, 152 in the development of high-performance spintronic devices including spin valve magnetic field sensors, 54,153 magnetic storage devices, and non-volatile magnetic random access memories. 55,154 Optimization of the geometry and size of patterned magnetic thin-film layers can boost the exchange bias field for spintronics applications.…”

Section: Layered Magnetic Nanomaterials and Exchange Anisotropymentioning

confidence: 99%