High temperature superconductor dc SQUID micro-susceptometer for room temperature objects

Faley, M.I.; Pratt, Kevin; Reineman, Richard; Schurig, David; Gott, Shannon C.; Atwood, Christopher G.; Sarwinski, R. E.; Paulson, D. N.; Starr, Tatiana; Fagaly, R.L.

doi:10.1088/0953-2048/17/5/046

Cited by 17 publications

(12 citation statements)

References 10 publications

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“…Our value of the relative magnetic field sensitivity is comparable to other methods used for measuring magnetic fields, such as squids [16] or atomic vapors [17,18]. Though it may be noted that the other methods target different applications, and while those can reach higher absolute sensitivity, our method relies only on a single ion, and can thus yield a very high spatial resolution, in the sub-µm range.…”

Section: B High Precision Detection Of Small Gradientssupporting

confidence: 50%

Single ion as a shot-noise-limited magnetic-field-gradient probe

et al. 2011

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It is expected that ion trap quantum computing can be made scalable through protocols that make use of transport of ion qubits between sub-regions within the ion trap. In this scenario, any magnetic field inhomogeneity the ion experiences during the transport, may lead to dephasing and loss of fidelity. Here we demonstrate how to measure, and compensate for, magnetic field gradients inside a segmented ion trap, by transporting a single ion over variable distances. We attain a relative magnetic field sensitivity of ∆B/B0 ∼ 5 · 10 −7 over a test distance of 140 µm, which can be extended to the mm range, still with sub µm resolution. A fast experimental sequence is presented, facilitating its use as a magnetic field gradient calibration routine, and it is demonstrated that the main limitation is the quantum shot noise.

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Section: B High Precision Detection Of Small Gradientssupporting

confidence: 50%

Single ion as a shot-noise-limited magnetic-field-gradient probe

et al. 2011

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“…This system was used to perform measurements of the magnetic field distribution over a US $1 bill, for a qualitative comparison of the device with SQUID microscope systems made by other groups [51,52]. The magnetic signal originates from the black ink used for printing banknotes, which contains a small quantity of magnetite (Fe 3 O 4 ) nanoparticles.…”

Section: High-tc Squid Microscope System With a Ferromagnetic Fluxmentioning

confidence: 99%

Superconducting Quantum Interferometers for Nondestructive Evaluation

Faley

Kostyurina

Kalashnikov

et al. 2017

Sensors

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We review stationary and mobile systems that are used for the nondestructive evaluation of room temperature objects and are based on superconducting quantum interference devices (SQUIDs). The systems are optimized for samples whose dimensions are between 10 micrometers and several meters. Stray magnetic fields from small samples (10 µm–10 cm) are studied using a SQUID microscope equipped with a magnetic flux antenna, which is fed through the walls of liquid nitrogen cryostat and a hole in the SQUID’s pick-up loop and returned sidewards from the SQUID back to the sample. The SQUID microscope does not disturb the magnetization of the sample during image recording due to the decoupling of the magnetic flux antenna from the modulation and feedback coil. For larger samples, we use a hand-held mobile liquid nitrogen minicryostat with a first order planar gradiometric SQUID sensor. Low-Tc DC SQUID systems that are designed for NDE measurements of bio-objects are able to operate with sufficient resolution in a magnetically unshielded environment. High-Tc DC SQUID magnetometers that are operated in a magnetic shield demonstrate a magnetic field resolution of ~4 fT/√Hz at 77 K. This sensitivity is improved to ~2 fT/√Hz at 77 K by using a soft magnetic flux antenna.

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“…Techniques that can characterize the magnetic properties, on the other hand, are limited. High temperature scanning superconducting quantum interference device (SQUID) measurements can image magnetic features but have a limited spatial resolution in the tens of micrometers, which is greater than the largest typical magnetic microbeads. Magnetic beads can be imaged by magnetic resonance imaging (MRI) and are in fact used as MRI contrast agents; however, the spatial resolution of MRI (typically on the order of millimeter, but reaching tens of micrometers) means it cannot determine the properties of individual beads.…”

Section: Introductionmentioning

confidence: 99%

Rapid, High‐Resolution Magnetic Microscopy of Single Magnetic Microbeads

McCoey

Gille

Nasr

et al. 2019

Small

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Magnetic microparticles or "beads" are used in a variety of research applications from cell sorting through to optical force traction microscopy. The magnetic properties of such particles can be tailored for specific applications with the uniformity of individual beads critical to their function. However, the majority of magnetic characterization techniques quantify the magnetic properties from large bead ensembles. Developing new magnetic imaging techniques to evaluate and visualize the magnetic fields from single beads will allow detailed insight into the magnetic uniformity, anisotropy, and alignment of magnetic domains. Here, diamond-based magnetic microscopy is applied to image and characterize individual magnetic beads with varying magnetic and structural properties: ferromagnetic and superparamagnetic/paramagnetic, shell (coated with magnetic material), and solid (magnetic material dispersed in matrix). The single-bead magnetic images identify irregularities in the magnetic profiles from individual bead populations. Magnetic simulations account for the varying magnetic profiles and allow to infer the magnetization of individual beads. Additionally, this work shows that the imaging technique can be adapted to achieve illumination-free tracking of magnetic beads, opening the possibility of tracking cell movements and mechanics in photosensitive contexts. Magnetic Materials www.advancedsciencenews.com

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High temperature superconductor dc SQUID micro-susceptometer for room temperature objects

Cited by 17 publications

References 10 publications

Single ion as a shot-noise-limited magnetic-field-gradient probe

Single ion as a shot-noise-limited magnetic-field-gradient probe

Superconducting Quantum Interferometers for Nondestructive Evaluation

Rapid, High‐Resolution Magnetic Microscopy of Single Magnetic Microbeads

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