Optimization of the magnetic properties of materials for fluxgate sensors

Benyosef, Luiz; Stael, Giovanni Chaves; Bochner, Maurício

doi:10.1590/s1516-14392008000200006

Cited by 21 publications

(11 citation statements)

References 18 publications

(21 reference statements)

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“…This is due to the fact that any value of magnetostriction, either positive or negative, links the mechanical stress on the core to the magnetization, producing a change of the voltage induced in the pick-up coil. A similar behaviour was experimentally observed with second harmonic parallel fluxgates [ 27 , 28 , 29 ] and is the reason why the composition of amorphous tapes was fine tuned when stress annealing was used to reduce the Barkhausen noise.…”

Section: Influence Of Annealing On the Magnetostrictionsupporting

confidence: 73%

An Improved Composition of CoFeSiB Alloy for Orthogonal Fluxgates

Butta

Janošek

Pařez

et al. 2022

Sensors

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Orthogonal fluxgates in fundamental mode based on (Co0.94Fe0.06)72.5Si12.5B15 cores have recorded very low noise in literature, especially if Joule annealing is performed on the core for a short period of time. However, for annealing time longer than 20–30 min, the noise of the sensor has a tendency to increase. In this work, we investigated this phenomenon, and we have found its origin in a monotonic increase of magnetostriction during the annealing process. We show that the wires with vanishing magnetostriction in their as-cast form exhibit positive magnetostriction after long-time annealing (more than 30 min), which increases the noise of the sensor. After researching the effect of the magnetostriction after annealing on the noise, we propose an alloy with a reduced amount of iron. Less iron leads to a larger as-cast negative magnetostriction, which becomes almost zero after long-time annealing (60 min), bringing further reduction of noise. We prove this effect on two wires from two different manufacturers, although with the same composition. The noise decrease with prolonged annealing is mainly observable in the low-frequency region: at 100 mHz, the noise of a single-wire sensor decreased from 20pT/Hz to 6pT/Hz when the annealing time was prolonged from 10 to 60 min.

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Section: Influence Of Annealing On the Magnetostrictionsupporting

confidence: 73%

An Improved Composition of CoFeSiB Alloy for Orthogonal Fluxgates

Butta

Janošek

Pařez

et al. 2022

Sensors

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“…For example, in the 1990s, Otto Neilson and others at the Danish Technical University (Nielsen et al, 1995) used an amorphous alloy to create the compact spherical coil (CSC) ring-core fluxgate magnetometer aboard the Orsted satellite. Also beginning in the 1990s, Luis Benyoseph of the National Observatory of Brazil has undertaken a long-term experimental effort to improve amorphous alloys for fluxgate sensors (Benyosef, 1996;Benyosef et al, 1995Benyosef et al, , 2008. More recently, Lajos Varga at the Hungarian Academy of Sciences developed amorphous materials for magnetometry (Lajos K. Varga, personal communication, 2013).…”

Section: Discussionmentioning

confidence: 99%

Low-noise permalloy ring cores for fluxgate magnetometers

Miles

Ciurzynski

Barona

et al. 2019

Geosci. Instrum. Method. Data Syst.

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Abstract. Fluxgate magnetometers are important tools for geophysics and space physics, providing high-precision magnetic field measurements. Fluxgate magnetometer noise performance is typically limited by a ferromagnetic element that is periodically forced into magnetic saturation to modulate, or gate, the local magnetic field. The parameters that control the intrinsic magnetic noise of the ferromagnetic element remain poorly understood. Much of the basic research into producing low-noise fluxgate sensors was completed in the 1960s for military purposes and was never publicly released. Many modern fluxgates depend on legacy Infinetics S1000 ring cores that have been out of production since 1996 and for which there is no published manufacturing process. We present a manufacturing approach that can consistently produce fluxgate ring cores with a noise of ∼6–11 pT per square root hertz – comparable to many of the legacy Infinetics ring cores used worldwide today. As a result, we demonstrate that we have developed the capacity to produce the low-noise ring cores essential for high-quality, science-grade fluxgate instrumentation. This work has also revealed potential avenues for further improving performance, and further research into low-noise magnetic materials and fluxgate magnetometer sensors is underway.

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“…In this work, we used a

{Co}_{67.5} {Fe}_{3.5} {Si}_{17.4} B_{11.6}

composition melted by melt-spinner method [10] and after submitted to a convenient stress-annealing technique [11] increasing its sensibility and reducing its noise level.…”

Section: Magnetometer Developmentmentioning

confidence: 99%

Autonomous Aeromagnetic Surveys Using a Fluxgate Magnetometer

Macharet

Perez-imaz

Rezeck

et al. 2016

Sensors

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Recent advances in the research of autonomous vehicles have showed a vast range of applications, such as exploration, surveillance and environmental monitoring. Considering the mining industry, it is possible to use such vehicles in the prospection of minerals of commercial interest beneath the ground. However, tasks such as geophysical surveys are highly dependent on specific sensors, which mostly are not designed to be used in these new range of autonomous vehicles. In this work, we propose a novel magnetic survey pipeline that aims to increase versatility, speed and robustness by using autonomous rotary-wing Unmanned Aerial Vehicles (UAVs). We also discuss the development of a state-of-the-art three-axis fluxgate, where our goal in this work was to refine and adjust the sensor topology and coupled electronics specifically for this type of vehicle and application. The sensor was built with two ring-cores using a specially developed stress-annealed CoFeSiB amorphous ribbon, in order to get sufficient resolution to detect concentrations of small ferrous minerals. Finally, we report on the results of experiments performed with a real UAV in an outdoor environment, showing the efficacy of the methodology in detecting an artificial ferrous anomaly.

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Optimization of the magnetic properties of materials for fluxgate sensors

Cited by 21 publications

References 18 publications

An Improved Composition of CoFeSiB Alloy for Orthogonal Fluxgates

An Improved Composition of CoFeSiB Alloy for Orthogonal Fluxgates

Low-noise permalloy ring cores for fluxgate magnetometers

Autonomous Aeromagnetic Surveys Using a Fluxgate Magnetometer

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