Hall-magnetometry on ferromagnetic dots and dot arrays

Schuh, Dieter; Biberger, J.; Bauer, Andreas; Breuer, W.; Weiss, Dieter

doi:10.1109/20.951063

Cited by 24 publications

(8 citation statements)

References 14 publications

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“…In temperature dependent measurements, one measures hysteresis loops over a wide temperature range [1,2]. From the temperature dependence of the switching field, one can calculate the height of the energy barrier.…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of the energy barrier and switching field of sub-micron magnetic islands with perpendicular anisotropy

2017

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Using the highly sensitive anomalous Hall effect we have been able to measure the reversal of a single magnetic island, of diameter 220 nm, in an array consisting of more than 80 of those islands. By repeatedly traversing the hysteresis loop, we measured the thermally induced fluctuation of the switching field of the islands at the lower and higher ends of the switching field distribution. Based on a novel easy-to-use model, we determined the switching field in the absence of thermal activation, and the energy barrier in the absence of an external field from these fluctuations. By measuring the reversal of individual dots in the array as a function of temperature, we extrapolated the switching field and energy barrier down to 0 K. The extrapolated values are not identical to those obtained from the fluctation of the switching field at room temperature, because the properties of the magnetic material are temperature dependent. As a result, extrapolating from temperature dependent measurements overestimates the energy barrier by more than a factor of two. To determine fundamental parameters of the energy barrier between magnetisation states, measuring the fluctuation of the reversal field at the temperature of application is therefore to be preferred. This is of primary importance to applications in data storagea and magnetic logic. For instance in fast switching, where the switching field in the absence of thermal activation plays a major role, or in long term data stability, which is determined by the energy barrier in the absence of an external field.

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Section: Introductionmentioning

confidence: 99%

Temperature dependence of the energy barrier and switching field of sub-micron magnetic islands with perpendicular anisotropy

2017

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“…At temperatures T < 80 K, such sensors effectively work as fluxmeters and are capable of resolving δΦ ≈10 -4 φ 0 , where φ 0 is a flux quantum. This technique has previously been used in studies of submicron superconducting [13,14] and ferromagnetic [19][20][21][22] particles, and its detailed description can be found therein. In the context of the present work, we have exploited this unique flux sensitivity to achieve an angstrom resolution in the average position of individual DWs.…”

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confidence: 99%

Subatomic movements of a domain wall in the Peierls potential

Новоселов

Geim

Dubonos

et al. 2003

Nature

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The discrete nature of crystal lattices plays a role in virtually every material property. But it is only when the size of entities hosted by a crystal becomes comparable to the lattice period--as occurs for dislocations, vortices in superconductors and domain walls--that this discreteness is manifest explicitly. The associated phenomena are usually described in terms of a background Peierls 'atomic washboard' energy potential, which was first introduced for the case of dislocation motion in the 1940s. This concept has subsequently been invoked in many situations to describe certain features in the bulk behaviour of materials, but has to date eluded direct detection and experimental scrutiny at a microscopic level. Here we report observations of the motion of a single magnetic domain wall at the scale of the individual peaks and troughs of the atomic energy landscape. Our experiments reveal that domain walls can become trapped between crystalline planes, and that they propagate by distinct jumps that match the lattice periodicity. The jumps between valleys are found to involve unusual dynamics that shed light on the microscopic processes underlying domain-wall propagation. Such observations offer a means for probing experimentally the physics of topological defects in discrete lattices--a field rich in phenomena that have been subject to extensive theoretical study.

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“…This technique has been used by different groups to measure stray field hysteresis loops of different nanostructures. (Hengstmann et al 2001;Rahm et al 2003a;Rahm et al 2003b;Schneider et al 2003;Schuh et al 2001) Rahm et al have used Hall sensors fabricated from GaAs/AlGaAs heterojunction material to measure stray field hysteresis loops of individual disks. (Rahm et al 2003b) Hall magnetometry on individual ferromagnetic disks has also been performed to study vortex pinning at single point defects.…”

Section: Hall Magnetometry On Magnetic Nanostructuresmentioning

confidence: 99%

Magnetic biosensors: Modelling and simulation

Nabaei

Chandrawati

Heidari

2018

Biosensors and Bioelectronics

143

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In the past few years, magnetoelectronics has emerged as a promising new platform technology in various biosensors for detection, identification, localisation and manipulation of a wide spectrum of biological, physical and chemical agents. The methods are based on the exposure of the magnetic field of a magnetically labelled biomolecule interacting with a complementary biomolecule bound to a magnetic field sensor. This Review presents various schemes of magnetic biosensor techniques from both simulation and modelling as well as analytical and numerical analysis points of view, and the performance variations under magnetic fields at steady and nonstationary states. This is followed by magnetic sensors modelling and simulations using advanced Multiphysics modelling software (e.g. Finite Element Method (FEM) etc.) and home-made developed tools. Furthermore, outlook and future directions of modelling and simulations of magnetic biosensors in different technologies and materials are critically discussed.

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Hall-magnetometry on ferromagnetic dots and dot arrays

Cited by 24 publications

References 14 publications

Temperature dependence of the energy barrier and switching field of sub-micron magnetic islands with perpendicular anisotropy

Temperature dependence of the energy barrier and switching field of sub-micron magnetic islands with perpendicular anisotropy

Subatomic movements of a domain wall in the Peierls potential

Magnetic biosensors: Modelling and simulation

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