Preferential orientation of magnetization and interfacial disorder in Co/Au multilayers

Quispe-Marcatoma, J.; Pandey, Brajesh; Alayo, W.; Sousa, Maria Alice Montes de; Pelegrini, F.; Baggio-Saitovitch, E.

doi:10.1016/j.jmmm.2013.05.045

Cited by 8 publications

(8 citation statements)

References 33 publications

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“…Magnetic patterns with the desired symmetry have been created by 10 keV He-ion bombardment induced magnetic patterning of magnetic multilayer structures with perpendicular magnetic anisotropy [49,54] using a home-built ion source for 5-30 keV He ions [55]. First, the layer system Ti 4nm /Au 60nm /[Co 0.7nm /Au 1nm ] 5 with M s of 1420 kA/m was fabricated by DC magnetron sputter deposition on a silicon substrate [56,57]. The sample's magnetic properties were characterized by polar magneto-optical Kerr effect magnetometry, possessing an initial coercive field of 19.5 ± 0.5 kA/m.…”

Section: B Lithographic Magnetic Structuresmentioning

confidence: 99%

Lattice symmetries and the topologically protected transport of colloidal particles

et al. 2017

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The topologically protected transport of colloidal particles on top of periodic magnetic patterns is studied experimentally, theoretically, and with computer simulations. To uncover the interplay between topology and symmetry we use patterns of all possible two dimensional magnetic point group symmetries with equal lengths lattice vectors. Transport of colloids is achieved by modulating the potential with external, homogeneous but time dependent magnetic fields. The modulation loops can be classified into topologically distinct classes. All loops falling into the same class cause motion in the same direction, making the transport robust against internal and external perturbations. We show that the lattice symmetry has a profound influence on the transport modes, the accessibility of transport networks, and the individual transport directions of paramagnetic and diamagnetic colloidal particles. We show how the transport of colloidal particles above a two fold symmetric stripe pattern changes from universal adiabatic transport at large elevations via a topologically protected ratchet motion at intermediate elevations toward a non-transport regime at low elevations. Transport above four-fold symmetric patterns is closely related to the two-fold symmetric case. The three-fold symmetric case however consists of a whole family of patterns that continuously vary with a phase variable. We show how this family can be divided into two topologically distinct classes supporting different transport modes and being protected by proper and improper six fold symmetries. We discuss and experimentally demonstrate the topological transition between both classes. All three-fold symmetric patterns support independent transport directions of paramagnetic and diamagnetic particles. The similarities and the differences in the lattice symmetry protected transport of classical over-damped colloidal particles versus the topologically protected transport in quantum mechanical systems are emphasized.

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Section: B Lithographic Magnetic Structuresmentioning

confidence: 99%

Lattice symmetries and the topologically protected transport of colloidal particles

et al. 2017

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“…Around 38 , 2θ value (main peak of Au), several satellite peaks are observed (see Figure 2), which are attributed to the superlattice Co/Au multilayer in agreement with the reported literature. 37 Along with it, a peak at 34 , 2θ is visible due to due to Co(211) crystal lattice plane. In the as-prepared condition, the deposition of only 1.5-nm Co on Au layer may lead to nonuniform distribution of Co grains over Au as Co tends to clusterize rather than mixing with Au due to high alloy formation energy.…”

Section: X-ray Diffractionmentioning

confidence: 94%

“…The authors have observed decrement in surface roughness in the sample with annealing which further suggested improvement in layer periodicity and sharpening of interfaces. Such studies provide a base for possible fabrication of magnetic sensors and other devices like magnetoresistance devices, 33,34 X‐ray and gamma ray optics, 35 magneto‐plasmonics, 36 and to study their spin dependent conductivity 33,36,37 …”

Section: Introductionmentioning

confidence: 99%

“…Such studies provide a base for possible fabrication of magnetic sensors and other devices like magnetoresistance devices, 33,34 X-ray and gamma ray optics, 35 magneto-plasmonics, 36 and to study their spin dependent conductivity. 33,36,37 However, a better knowledge of growth, structure along with the magnetic orientation, and pertaining magnetic domain structure of layers and their interfaces is worth studying. Because Co and Au form an immiscible system up to very high temperatures of annealing with a positive heat of formation of +11 kJ mol −1 , it is possible that upon mild annealing of this MLS, Co may get clusterized, thereby destroying the layered structure.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic transition in ultrathin Co sandwiched between Au layers in [Au (3.16 nm)/Co (1.5 nm)]_x35/Si(100) multilayers

Tripathi

Sharma

Kumar

et al. 2020

Surface & Interface Analysis

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The superparamagnetic to ferromagnetic transition in ultrathin Co layers has been investigated by systematic annealing of Co ultrathin layer sandwiched between a pair of Au layer in the [Au (3.16 nm)/Co (1.5 nm)]x35/Si(100) multilayers. Apart from this magnetic transition, annealing‐induced modifications in morphological and structural properties of this discontinuous island like Co ultrathin layer have also been investigated. The thickness and number of Co and Au layers were so chosen as to make a composition of 20 weight percent (wt%) Co in Au matrix. X‐ray diffraction and reflectivity measurements reveal the formation of a bilayer stack showing Bragg's peaks, which disappear upon annealing beyond 200°C due to mixing of layers. Corresponding SQUID results show a transition from superparamagnetic to ferromagnetic phase beyond 200°C, indicating the clusterization of Co, which is enabled by nonmiscible nature of Co and Au. The results are interpreted in terms of annealing‐dependent mobility of Co and Au atoms resulting in superparamagnetic to ferromagnetic and finally to a non‐magnetic phase.

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“…The experimental results also show that the DW in the SAF nanowire is able to move faster than a DW in typical ferromagnetic system due to the fact that the DW in the SAF system is more rigid. Other multilayer structures other than the SIA have also been investigated in order to find the most suitable candidate for high DW speed [62][63][64][65][66][67][68][69][70][71][72][73][74]. It was shown that in a bilayer PMA structure, that there is a possibility that the DWs are aligned oppositely in the Néel configuration.…”

Section: Magnetic Domain Wallsmentioning

confidence: 99%

Dynamics of current-driven magnetic domain walls and skyrmions

Purnama¹

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The dynamics of current-driven magnetic domain walls and skyrmions are both topics of high interest in the magnetism community due to the possibility of employing them in novel high-density non-volatile memory devices. One such device is the well-known racetrack memory, where the information is stored in a ferromagnetic nanowire as compared to the conventional harddisk memory, while the operation is mediated via the injection of current to the nanowire. In a domain wall-based racetrack memory, the information is represented by magnatic domains that are separated by domain walls, while in a skyrmionbased racetrack memory, the information is represented by the presence of the skyrmions themselves. However, to be able to realize such devices, it is very important to have a complete understanding of both the domain wall and dynamics under the application of current. At present, the investigation of domain wall dynamics is mainly focused on finding additional driving mechanisms to improve its mobility. In the case of skyrmion dynamics, the research is still in the very early stage, although it has been shown that it is possible to inject individual skyrmions individually which brings skyrmion-based devices closer to realization. In this thesis, the dynamics of current driven magnetic domain walls and skyrmions in various nanostructures are investigated. We show by micromagnetic simulations that it is possible to drive multiple domain walls in a multi-nanowire system by just applying current to one of the nanowires. The phenomenon is made possible due to the magnetostatic coupling between the domain walls. When materials with in-plane anisotropy are considered, the coupling is realized when the nanowires are placed parallel to each other, and the technique can be further utilized to drive several domain walls in the current-free nanowire. When materials with strong perpendicular magnetization anisotropy are used, the phenomenon is realized by stacking the nanowires vertically, and the coupling between the

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Preferential orientation of magnetization and interfacial disorder in Co/Au multilayers

Cited by 8 publications

References 33 publications

Lattice symmetries and the topologically protected transport of colloidal particles

Lattice symmetries and the topologically protected transport of colloidal particles

Magnetic transition in ultrathin Co sandwiched between Au layers in [Au (3.16 nm)/Co (1.5 nm)]_x35/Si(100) multilayers

Dynamics of current-driven magnetic domain walls and skyrmions

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Preferential orientation of magnetization and interfacial disorder in Co/Au multilayers

Cited by 8 publications

References 33 publications

Lattice symmetries and the topologically protected transport of colloidal particles

Lattice symmetries and the topologically protected transport of colloidal particles

Magnetic transition in ultrathin Co sandwiched between Au layers in [Au (3.16 nm)/Co (1.5 nm)]x35/Si(100) multilayers

Dynamics of current-driven magnetic domain walls and skyrmions

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Magnetic transition in ultrathin Co sandwiched between Au layers in [Au (3.16 nm)/Co (1.5 nm)]_x35/Si(100) multilayers