Structure and Magnetic Properties of Thin Permalloy Films Near the “Transcritical” State

Svalov, A. V.; Aseguinolaza, I. R.; Garcı́a-Arribas, A.; Orúe, I.; Barandiarán, J.M.; Alonso, Jesús José Beltrán de Heredia; Fernández-Gubieda, M. L.; Kurlyandskaya, G.V.

doi:10.1109/tmag.2009.2032519

Cited by 122 publications

(94 citation statements)

References 14 publications

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“…The disk is made of Ni 80 Fe 20 and the magnetization path is separated from the disk by a 100 nm SiN 3 passivation layer. The parameters for Ni 80 Fe 20 were taken from previous studies, [36][37][38][39][40][41][42] the diameter of the disk is 3 lm, and the thickness of the disk is 30 nm. The disk's diameter influences several parameters like the magnetic properties or the number of SPBs that can be trapped at a disk.…”

Section: -3mentioning

confidence: 99%

“…This is ideal for our experiments, since the demagnetization procedure could be challenging, when disks are fully magnetized. [36][37][38][39][40][41][42] For our experiments, it is important that the disks are magnetized and demagnetized by simply turning the current on and off.…”

Section: A Characterization Of Soft Ferromagnetic Disksmentioning

confidence: 99%

“…These values agree well with previous studies on permalloy disks. 36,37,42 The saturation field can also be estimated by taking into account the shape anisotropy given by the aspect ratio s ¼ d/t, where d and t are the diameter and thickness of the disk, respectively. The magnetic field inside the disk H disk is a function of the applied field H app and the demagnetizing field H d…”

Section: A Characterization Of Soft Ferromagnetic Disksmentioning

confidence: 99%

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Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

et al. 2014

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This study describes the development and testing of a magnetic microfluidic chip (MMC) for trapping and isolating cells tagged with superparamagnetic beads (SPBs) in a microfluidic environment for selective treatment and analysis. The trapping and isolation are done in two separate steps; first, the trapping of the tagged cells in a main channel is achieved by soft ferromagnetic disks and second, the transportation of the cells into side chambers for isolation is executed by tapered conductive paths made of Gold (Au). Numerical simulations were performed to analyze the magnetic flux and force distributions of the disks and conducting paths, for trapping and transporting SPBs. The MMC was fabricated using standard microfabrication processes. Experiments were performed with E. coli (K12 strand) tagged with 2.8 μm SPBs. The results showed that E. coli can be separated from a sample solution by trapping them at the disk sites, and then isolated into chambers by transporting them along the tapered conducting paths. Once the E. coli was trapped inside the side chambers, two selective treatments were performed. In one chamber, a solution with minimal nutrition content was added and, in another chamber, a solution with essential nutrition was added. The results showed that the growth of bacteria cultured in the second chamber containing nutrient was significantly higher, demonstrating that the E. coli was not affected by the magnetically driven transportation and the feasibility of performing different treatments on selectively isolated cells on a single microfluidic platform.

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Section: -3mentioning

confidence: 99%

Section: A Characterization Of Soft Ferromagnetic Disksmentioning

confidence: 99%

Section: A Characterization Of Soft Ferromagnetic Disksmentioning

confidence: 99%

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Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

et al. 2014

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“…increase. The second feature is due to the beginning of the transition of the FeNi layers into a "transcritical" state always resulting in the coercivity increase [8][9]. The appearance of the H c peak at L FeNi ~ 100 nm for Ti/FeNi films seems to be connected with a transition of the structure of the domain walls caused by an increase of the FeNi film thickness.…”

Section: Resultsmentioning

confidence: 94%

Structure and magnetic properties of FeNi/Ti sputtered multilayers

Alzola

Svalov

Mayura

et al. 2013

EPJ Web of Conferences

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Abstract. The microstructure, anisotropic magnetoresistance, magnetic properties and magnetic domain structure of sputtered FeNi films and [Ti/FeNi] n (n = 2-16) multilayers were comparatively analyzed. It was found that although the grain size increases with an increase of the FeNi thickness both in the case of FeNi films and [Ti/FeNi] n multilayers, it did not exceed 25 nm. The values of anisotropic magnetoresistance for FeNi films and [Ti/FeNi] n multilayers were close to each other showing a weak dependence on the total thickness of the multilayered structure. Coercivity for multilayers was found to be smaller than the coercivity of single layer FeNi films. Despite the absence of a direct exchange interaction between FeNi neighboring layers in the [Ti/FeNi] n structures, their domain structures were found to be quite different from magnetic domains in single layer films due to stray field compensation in the multilayers. Obtained results are useful for the development of sensitive elements for small magnetic field detectors and planar inductors.

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“…Therefore, it is very important to determine the optimum preparation conditions, as well as the limiting Py single-layer thickness that can be reached before entering the transcritical state. In low pressure sputtering deposition, this thickness is determined to be about 170 nm [28]. To increase the total effective thickness, it has been proposed to use thin spacers between successive Py layers, creating a thick magnetic multilayer in which all the Py films are below the critical thickness [29,30].…”

Section: Thin Film MI Materialsmentioning

confidence: 99%

Thin-Film Magneto-Impedance Sensors

Garcı́a-Arribas¹,

Férnández²,

Cos³

2017

Magnetic Sensors - Development Trends and Applications

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We review the state-of-the-art of thin films displaying the magneto-impedance (MI) effect, with focus on the aspects that are relevant to the successful design and operation of thin film-based magnetic sensors. After a brief introduction of the MI effect, the materials and geometries that maximize the performance, together with the measurement procedure for their characterization, are exposed. A nonexhaustive survey of applications is included, mostly with the aim of displaying the capabilities of thin film structures in the field of magnetic sensing, and the variety of topics covered by them. A special emphasis is made on some concepts that are not commonly treated in the literature, such as the influence of the measuring circuit on the magneto-impedance ratio, the geometry optimization by means of numerical simulation by finite element methods, or noise measurements on thin films. Additionally, a brief description of the patterning procedure by photolithography is included, since the major advantage of thin film sensors over other types of magneto-impedance materials as ribbons or wires is the possibility of patterning the sensible element in micrometric shapes, and most of all, their easy integration with the interface microelectronic circuitry.

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Structure and Magnetic Properties of Thin Permalloy Films Near the “Transcritical” State

Cited by 122 publications

References 14 publications

Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

Structure and magnetic properties of FeNi/Ti sputtered multilayers

Thin-Film Magneto-Impedance Sensors

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