Magnetic domain studies of permalloy wire-based structures with junctions

Hirohata, Atsufumi; Yao, C.C.; Leung, H.T.; Xu, Yongbing; Guertler, C. M.; Bland, J. A. C.

doi:10.1109/20.908682

Cited by 15 publications

(5 citation statements)

References 11 publications

(15 reference statements)

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“…We observe sections of the chain in which neighboring vortices have the same chirality, implying that at the nodes moments from the neighboring rings have opposite orientation and that a domain boundary forms. 24 Consequently, magnetic contrast is clearly visible at the nodes separating rings with the same chirality ͓cf. frame ͑c͔͒.…”

Section: Resultsmentioning

confidence: 99%

Magnetization reversal in arrays of Co rings

et al. 2003

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The magnetization behavior of arrays of individual and coupled Co rings has been studied using superconducting quantum interference device magnetometry, magneto-optical imaging, and Lorentz transmission and scanning transmission electron microscopy. The transition from the polarized into the vortex state of isolated rings is shown to occur through the motion and annihilation of head-to-head domain boundaries. The chirality of the vortex state is fixed on subsequent magnetization cycles, indicating that it is predetermined by structural imperfections of the rings. The effect of interactions between the rings has been investigated in arrays of chains of touching rings. For fields applied parallel to the chains rings in extended sections of the chains are found to switch simultaneously. Neighboring rings in these sections can display alternating chirality as well as the same chirality accompanied by a 180°boundary on the nodes. For fields perpendicular to the chain direction the switching occurs pairwise. This coupling introduces a broad distribution of switching fields and correspondingly a magnetization curve that is significantly broader than that for the parallel orientation.

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Section: Resultsmentioning

confidence: 99%

Magnetization reversal in arrays of Co rings

et al. 2003

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“…In addition to potential technological applications, the high-symmetry ring geometry has proven to be valuable for the investigation of fundamental physical questions, such as the pinning and structure of domain walls at notches (constrictions) [13,14], magnetoresistance effects associated with domain walls [14], and quantum effects such as Aharonov-Bohm oscillations [15]. While in this article we discuss non-interacting isolated rings, earlier work in our group by Hirohata et al [16] and work by Welp et al [17] has elucidated the properties of ring chains. The related square ring geometry ('picture frame') has also been investigated [18].…”

Section: Introductionmentioning

confidence: 99%

Vortex formation in narrow ferromagnetic rings

Kläui

Vaz

López-Dı́az

et al. 2003

J. Phys.: Condens. Matter

254

228

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The high-symmetry ring geometry is shown to exhibit a wide range of intriguing magnetostatic and magnetodynamic properties, which we survey in this topical review. We consider first the patterning and deposition techniques, which are used to fabricate ring structures (diameters between 0.1 and 2 µm) and discuss their respective advantages and disadvantages. The results of direct nanoscale imaging of the novel magnetization configurations present in rings with different geometrical parameters (including discs) are discussed. These results give valuable insight into the influence of the magnetic anisotropies governing the magnetic states. The different types of domain walls that arise are compared quantitatively to micromagnetic simulations. The magnetodynamic switching between the different magnetic states is described in detail. In particular we elaborate on the different geometry-dependent magnetic switchings, since the different transitions occurring allow us to determine which energy terms govern the reversal process. We discuss a process by which fast (sub-ns) and controlled switching can be achieved, therefore making rings an attractive geometry for applications, in addition to studying fundamental issues of nanomagnetism.

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“…A higher ratio of l/w around ten conjugated with less thickness of NiFe FM layer for cross shape, leads to triple increase of sensitivity, attributed to shape anisotropy elevation as reported [53]. Different square, rectangle, rhombus and circle Permalloy films are introduced with a varied length to width ratio from 1 to 29, where square shape shows the maximum sensitivity [204,205]. The impact of the width of the junction arm is stipulated in terms of shape anisotropy.…”

Section: Impact Of Junction Dimensions (L/w) On Sensor Performancementioning

confidence: 97%

Current trends in planar Hall effect sensors: evolution, optimization, and applications

Elzwawy

Pişkin

Akdoğan

et al. 2021

J. Phys. D: Appl. Phys.

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The advantages of planar Hall effect (PHE) sensors-their thermal stability, very low detection limits, and high sensitivities-have supported a wide range of advanced applications such as nano-Tesla (nT) magnetometers, current sensing, or low magnetic moment detection in lab-on-a-chip devices. In this review we outline the background and implications of these PHE sensors, starting from fundamental physics through their technological evolution over the past few decades. Key parameters affecting the performance of these sensors, including noise from different sources, thermal stability, and magnetoresistance magnitudes are discussed. The progression of sensor geometries and junctions from disk, cross-to-bridge, ring, and ellipse configuration is also reviewed. The logical sequence of these structures from single magnetoresistive layers to bi-, tri-layers, and spin-valves is also covered. Research contributions to the development of these sensors are highlighted with a focus on microfluidics and flexible sensorics. This review serves as a comprehensive resource for scientists who wish to use PHE for fundamental research or to develop new applications and devices. The conclusions from this report will benefit the development, production, and performance evaluation of PHE-based devices and microfluidics, as well as set the stage for future advances.

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Magnetic domain studies of permalloy wire-based structures with junctions

Cited by 15 publications

References 11 publications

Magnetization reversal in arrays of Co rings

Magnetization reversal in arrays of Co rings

Vortex formation in narrow ferromagnetic rings

Current trends in planar Hall effect sensors: evolution, optimization, and applications

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