Size, Weight and Power Efficiency for High-power, Nonlinear, Geophysical-transmitter, Rod-core Antennas

Jordan, Jared Williams; Sternberg, Ben K.; Dvorak, S.L.

doi:10.2113/jeeg16.1.1

Cited by 2 publications

(1 citation statement)

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“…Magnetic wires have been used as functional materials of fluxgate magnetic field sensors since the 1930s, and some of these devices are still in production. The magnetic core of these sensors is typically a permalloy (NiFe) wire with a diameter of 0.2 mm, but some fluxgates and induction sensors use core in the form of rod with length up to 1 m [1]. While wire-core fluxgates usually do not achieve the low noise and the high offset stability of ring-core fluxgate sensors made of thin tape, wire cores of Vacquier type show several fundamental advantages [2]:…”

Section: Introductionmentioning

confidence: 99%

Modelling and Measurement of Magnetically Soft Nanowire Arrays for Sensor Applications

Ripka

Grim

Mirzaei

et al. 2020

Sensors

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Soft magnetic wires and microwires are currently used for the cores of magnetic sensors. Due to their low demagnetization, they contribute to the high sensitivity and the high spatial resolution of fluxgates, Giant Magnetoimpedance (GMI), and inductive sensors. The arrays of nanowires can be prepared by electrodeposition into predefined pores of a nanoporous polycarbonate membrane. While high coercivity arrays with square loops are convenient for information storage and for bistable sensors such as proximity switches, low coercivity cores are needed for linear sensors. We show that coercivity can be controlled by the geometry of the array: increasing the diameter of nanowires (20 µm in length) from 30 nm to 200 nm reduced the coercivity by a factor of 10, while the corresponding decrease in the apparent permeability was only 5-fold. Finite element simulation of nanowire arrays is important for sensor development, but it is computationally demanding. While an array of 2000 wires can be still modelled in 3D, this is impossible for real arrays containing millions of wires. We have developed an equivalent 2D model, which allows us to solve these large arrays with acceptable accuracy. Using this tool, we have shown that as a core of magnetic sensors, nanowires are efficiently employed only together with microcoils with diameter comparable to the nanowire length.

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Section: Introductionmentioning

confidence: 99%