Abstract
High sensitivity is often the foremost characteristic for magnetic field sensors; however, the most sensitive systems tend to be attributed with being any combination of large in size, high in power consumption, complex in design, or exorbitant in cost. This fact not only limits accessibility to the technology afforded by high sensitivity sensing, but it also restricts the extent to which potential applications of magnetic field sensing may be realized. Herein we propose a concept for sensor operation that can achieve sensitivities competitive with those of modern magnetic field sensors while simultaneously maintaining small size, low power consumption, simplicity in design, and low cost. This is accomplished through employment of the nonlinear precession dynamics of electron spins to attain parametric amplification of a magnetic field. A preliminary experimental implementation of the proposed concept establishes its feasibility and is already able to demonstrate benefits over existing approaches to sensing. The implementation exhibits a sensitivity of 23.2 pT/Hz<sup>1/2</sup> with a volume of 0.0564 mm<sup>3</sup> and a power consumption of −40.96 dBm.
Highlights
Magnetic field sensors have been one of the cornerstone technologies in advancing the progress of research and development in many areas
Super quantum interference device (SQUID) sensors operate based on the quantization of magnetic flux, optically pumped sensors operate based on atomic magneto-optic effects, induction sensors operate based on Faraday’s law of induction, and magnetic tunnel junction sensors operate based on polarization dependent electron tunneling [1]
We introduce an approach that exploits nonlinear dynamics in magnetic materials to realize sensitive magnetic field sensors that maintain a high degree of practicality
Summary
Magnetic field sensors have been one of the cornerstone technologies in advancing the progress of research and development in many areas. Ferrites have been used extensively in high frequency electronics [16], [17] with well-established processing methods [18] that allow the material to be produced relatively inexpensively While some of these same attributes have motivated the use of ferrites for inductive sensors [19]–[23], these sensors do not rely on nonlinear spin precession dynamics like RPM sensors do. Equation (2) is the core of optically pumped sensor operation where it is evident that, in determining ω0 in some way, an unknown H0 can be directly computed [15] We suggest that a bias field with a time varying magnitude H0 + hs (t) will yield a time varying angular precession frequency ω (t) = ω0 + μ0γ hs (t). We consider the case in which other physics, the demagnetization field, contribute significantly to the effective field
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