Suppression Of Magnetic Noise Research Articles

Suppression of Magnetic Noise and Field in Cubic Low-Noise Ferrite Magnetic Shields

Suppression of Magnetic Noise and Field in Cubic Low-Noise Ferrite Magnetic Shields

Effect of Complex Permeability on Circuit Parameters of CPW with Magnetic Noise Suppression Sheet

Effect of Complex Permeability on Circuit Parameters of CPW with Magnetic Noise Suppression Sheet

The characteristic analysis of a nuclear magnetic resonance oscillator coupled with the phase-locked loop

We analyze the scale factor linearity, steady-state, transient, and noise characteristics of a nuclear magnetic resonance oscillator coupled with the phase-locked loop, which makes its performance improvement possible by a balanced strategy in optimizing parameters based on the proposed model. The numerical simulation indicates that the simple oscillator system gives a better scale factor linearity and transient response than the coupled system, while the steady-state solution is similar between the two with experimental validation. The phase and magnetic noise suppression is necessary to ensure the dynamic response of the coupled system. The characteristic analysis not only facilitates the rapid-response optimization of the coupled oscillator system under a dynamic environment but also enlightens corresponding steady-state tracking precision.

Antiparallel exchange biased multilayers for low magnetic noise magnetic field sensors

High sensitivity magnetoelectric (ME) thin film composite sensors, which enable the detection of picotesla magnetic fields, are improved in terms of magnetic noise performance by the elimination of magnetic domain (MD) activity. Using an antiparallel (AP) exchange biasing scheme, suppression of magnetic noise is obtained. Postsetting of AP biased ferromagnetic/antiferromagnetic multilayers is accomplished by magnetic field free annealing with in-situ MD control. Overcoming the shape and demagnetization effects, stable single MD configurations in the magnetic sensing layers of magnetic multilayers are formed. Magnetic noise contributions are undetectable. The achieved single domain field stability opens the path to ultralow noise ME sensor applications. The demonstrated AP biasing scheme is applicable to other magnetic layer-based field sensing devices.

Suppression of magnetic noise in the fundamental-mode orthogonal fluxgate

A new important advantage has been discovered for the fundamental-mode operation of the orthogonal fluxgate employing an amorphous wire. It has been found that a great enough dc bias practically completely suppresses the magnetic noise generated in the fluxgate core by the ac-bias field; the fluxgate resolution becomes limited only by the excess electric noise in the ac-bias current. As a result, the magnetometer resolution increases by a factor of 60 and reaches 10 pT/ Hz at frequencies above 2 Hz. The suppression of magnetic noise can be explained by excluding magnetization reversals in the fluxgate core. In the fundamental mode, the fluxgate core is kept saturated continuously due to the unipolar bias, and magnetization varies by coherent rotation. Practically no magnetic noise is generated in this case. In the second-harmonic mode, magnetization is reversed by the bipolar bias. This causes nucleating domains and generating intensive magnetic noise in the fluxgate core.