Novel scanning dc-susceptometer for characterization of heat-resistant steels with different states of aging

Pereira, J.A.M.; Pacheco, Clara Johanna; Arenas, Mónica P.; Araújo, Jefferson F.D.F.; Pereira, Gabriela Ribeiro; Bruno, A. C.

doi:10.1016/j.jmmm.2017.07.004

Cited by 20 publications

(16 citation statements)

References 15 publications

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“…In the current configuration, the microscope was equipped with commercial Hall-effect sensors, as shown in Supplementary Materials Figure S1 in the ESI. The output noise measured at 6 Hz was approximately 520 nT rms / √ Hz (± 10 nT rms / √ Hz) in a protected environment, and the magnetic moment sensitivity was 9.20 × 10 −10 Am 2 [5,[13][14][15]. The standard deviation of the measurements was approximately 0.04 × 10 −10 Am 2 (about 0.38%) for the remanent magnetization.…”

Section: Introductionmentioning

confidence: 93%

“…The calibration process of the magnetic microscope consists of acquiring the distance on the z-axis between the sensitivity region of the Hall-effect sensors and the surface of the sample using only circuit boards and measuring the sample remanent fields with a 99% purity nickel sphere magnetized at 0.5 T to determine the distance [13][14][15]17,18]. The nickel sphere was placed in a sample holder made of acrylic material with a cylindrical cavity (see Figure 2a).…”

Section: Calibration and Magnetic Measurementsmentioning

confidence: 99%

“…Figure 2b shows the map of the remanent magnetic field of the nickel sphere. Using the magnetic map and the model of a magnetic dipole, the magnetic moment of the nickel sphere was determined [5,13]. After finding the magnetic moment of the nickel sphere, it was possible to estimate the distance between the sensitivity region of sensor A and the surface of the sample, which was approximately 115 µm.…”

Section: Calibration and Magnetic Measurementsmentioning

confidence: 99%

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Scanning Magnetic Microscope Using a Gradiometric Configuration for Characterization of Rock Samples

et al. 2019

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Scanning magnetic microscopy is a tool that has been used to map magnetic fields with good spatial resolution and field sensitivity. This technology has great advantages over other instruments; for example, its operation does not require cryogenic technology, which reduces its operational cost and complexity. Here, we presented a spatial domain technique based on an equivalent layer approach for processing the data set produced by magnetic microscopy. This approach estimated a magnetic moment distribution over a fictitious layer composed by a set of dipoles located below the observation plane. For this purpose, we formulated a linear inverse problem for calculating the magnetic vector and its amplitude. Vector field maps are valuable tools for the magnetic interpretation of samples with a high spatial variability of magnetization. These maps could provide comprehensive information regarding the spatial distribution of magnetic carriers. In addition, this approach might be useful for characterizing isolated areas over samples or investigating the spatial magnetization distribution of bulk samples at the micro and millimeter scales. This technique could be useful for many applications that require samples that need to be mapped without a magnetic field at room temperature, including rock magnetism.

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Section: Introductionmentioning

confidence: 93%

Section: Calibration and Magnetic Measurementsmentioning

confidence: 99%

Section: Calibration and Magnetic Measurementsmentioning

confidence: 99%

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Scanning Magnetic Microscope Using a Gradiometric Configuration for Characterization of Rock Samples

et al. 2019

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“…The distribution of magnetization in the thin section was obtained using a custom-made magnetic scanning microscope in the Instrumentation and Magnetic Measurement Laboratory of the Physics Department of Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio) in Brazil. The equipment was developed by Pereira et al (2017), and its potential use in rock thin sections was outlined by Araujo et al (2019). The microscope operates with a pair of commercial Hall effect sensors.…”

Section: Magnetic Scanning Microscopymentioning

confidence: 99%

Magnetic Properties of Ferritchromite and Cr‐Magnetite and Monitoring of Cr‐Spinels Alteration in Ultramafic and Mafic Rocks

Hodel

Macouin

Trindade

et al. 2020

Geochem Geophys Geosyst

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“…A low-noise preamplifier (SR560, SRS Inc.) accomplishes the gradiometer operation by electronically subtracting the two output signals. In the first version, the current sources were based on the IC LM334 and controlled by resistance, showing a high noise and strong temperature dependence, even when using a temperature compensation circuit [19]. Then, we redesigned the circuit by replacing the LM334, for the two current sources that are controlled by voltage with the INA105.…”

Section: Custom Electronicsmentioning

confidence: 99%

Characterizing Complex Mineral Structures in Thin Section of Geological Sample with a Scanning Hall Effect Microscope

Araújo¹,

Reis²,

Oliveia³

et al. 2019

Preprint

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We improved a magnetic scanning microscope for measuring the magnetic properties of minerals in thin sections of geological samples at submillimeter scales. The microscope is comprised of a 200 µm diameter Hall sensor that is 142 µm from the sample; an electromagnet capable of applying to the sample up to 500 mT dc magnetic fields over a 40 mm diameter region; a second Hall sensor arranged in a gradiometric configuration to cancel the background signal applied by the electromagnet and reduce overall noise in the system; a custom-designed electronics to bias the sensors and provide adjustment for background signal cancelation; and a scanning XY stage with micrometer resolution. Our system achieves a spatial resolution of  220 µm with noise at 6.0 Hz of »300 nTrms/(Hz)1/2 in an unshielded environment. The magnetic moment sensitivity is 1.3 × 10−11 Am2.1/2 We successfully measured the representative magnetization of a geological sample using an alternative model that takes into account the sample geometry and identified different micrometric characteristics in the sample slice.

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Novel scanning dc-susceptometer for characterization of heat-resistant steels with different states of aging

Cited by 20 publications

References 15 publications

Scanning Magnetic Microscope Using a Gradiometric Configuration for Characterization of Rock Samples

Scanning Magnetic Microscope Using a Gradiometric Configuration for Characterization of Rock Samples

Magnetic Properties of Ferritchromite and Cr‐Magnetite and Monitoring of Cr‐Spinels Alteration in Ultramafic and Mafic Rocks

Characterizing Complex Mineral Structures in Thin Section of Geological Sample with a Scanning Hall Effect Microscope

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