Noise and response characterization of an anisotropic magnetoresistive sensor working in a high-frequency flipping regime

We report on the design, construction, and performance of a compact magnetic shield that facilitates a controlled, low-noise environment for experiments with ultracold atomic gases. The shield was designed to passively attenuate external slowly-varying magnetic fields while allowing for ample optical access. The geometry, number of layers and choice of materials were optimised using extensive finite-element numerical simulations. The measured performance of the shield is in good agreement with the simulations. From measurements of the spin coherence of an ultracold atomic ensemble we demonstrate a remnant field noise of 2.6 µG and a suppression of external dc magnetic fields by more than five orders of magnitude.

Section: Introductionmentioning

confidence: 99%

Design and characterization of a compact magnetic shield for ultracold atomic gas experiments

Farolfi

Trypogeorgos

Colzi

et al. 2019

“…The measured rms noise amounts to 3.3 LSB and, as discussed in Ref. 13, is field independent. Taking into account the static field response analysis of Sec.…”

Section: Noise Characterizationmentioning

confidence: 61%

“…These parameters have been set to 0.5 A and 8 s, respectively, on the basis of the noise and response characterization described in Ref. 13.…”

Section: Operation Timingmentioning

confidence: 99%

Magnetoresistive magnetometer with improved bandwidth and response characteristics

Bertoldi

Bassi

Ricci

et al. 2005

We report on the realization and characterization of a high performance, compact magnetometer based on a magnetoresistive sensor and working in the range ±600 T. The output is provided both numerically and by means of a field-proportional voltage. Spurious offset effects are suppressed by flipping the film magnetization at a frequency of 100 kHz, 2 / 3 orders of magnitude higher than in conventional applications. The design allows for a field resolution of 20 nT, low output noise density, and high precision and accuracy ͑relative full-scale uncertainty of about 500 ppm͒.

“…The magnetometers used 10 are compact instruments based on commercially available magnetoresistive sensors. 11 Each magnetometer is made up of a measurement head and a remote console; the magnetic field is measured in a single direction within the range of ±600 T, at a rate of 100 kHz, with a relative full-scale uncertainty of about 500 ppm and a resolution of 20 nT. The printed circuit board corresponding to the measurement head has a size of 70ϫ 53 mm 2 and hosts the magnetoresistive probe ͑size of 4.9ϫ 3.9 ϫ 1.5 mm 3 ͒ as well as a conditioning and analog-to-digital conversion circuitry.…”

Section: Methodsmentioning

confidence: 99%

Noninvasive system for the simultaneous stabilization and control of magnetic field strength and gradient

Botti

Buffa

Bertoldi

et al. 2006

We report on the realization and characterization of a system for the simultaneous stabilization and control of magnetic field strength and gradient in a region of 35 mm and along a given direction. The system is based on two magnetometers, each providing a field readout every 10 s, and a control unit, which real-time processes the readouts and controls the currents flowing into two compensation coils. Attenuations of 30 dB for the field strength and 20 dB for the gradient have been achieved, along with feedback loop bandwidths of 450 and 620 Hz, respectively. The method can be extended in order to noninvasively control the field strength and gradient along all three directions as well as higher-order multipole terms.