Quantitative current measurements using scanning magnetoresistance microscopy

Takezaki, T.; Sueoka, Kazuhisa

doi:10.1016/j.ultramic.2008.03.007

Cited by 4 publications

(6 citation statements)

References 10 publications

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“…A representative sensitivity characterisation of the used TMR sensor batch is presented in a previous publication [ 20 ], with an estimated sensitivity of S se ≈ 175 µ V/Oe with a minimum detectable field of 0.2–1.3 Oe, varying from sensor to sensor. This compares well with a spin valve-based scanning magnetoresistance microscope [ 21 ], which specifies a sensitivity of 14.8 µ V/Oe and shows measured magnetic fields down to ∼1.3 Oe.…”

Section: Instrument Designsupporting

confidence: 79%

“…Assuming a bandwidth of 1 Hz and a 10 µ A excitation current, the expected magnetic field sensitivity ( SNR = 1) is 175 µ Oe. This is slightly higher than the theoretical limit published in [ 21 ] for an out-of-plane MR scanning system. In [ 21 ], the minimum detected field is 1.3 Oe, whilst our system detected fields as low as 0.25 Oe.…”

Section: Characterisationmentioning

confidence: 54%

“…This is slightly higher than the theoretical limit published in [ 21 ] for an out-of-plane MR scanning system. In [ 21 ], the minimum detected field is 1.3 Oe, whilst our system detected fields as low as 0.25 Oe. Furthermore, as the current system operates at low frequencies, where we are 1/ f -limited [ 22 , 23 ], we believe that there is significant scope for further improvement in the minimum detectable field.…”

Section: Characterisationmentioning

confidence: 54%

“…Another benefit of high-frequency operation is overcoming 1/ f noise. Assuming then that we are Johnson noise limited, the theoretical minimum detectable field is determined by the following equation [ 21 ]:

where SNR is the signal-to-noise ratio, S se is sensor sensitivity, H is the applied magnetic field, k B is the Boltzmann constant, T is temperature, R S is sensor resistance and ∆ f is the bandwidth. Assuming a bandwidth of 1 Hz and a 10 µ A excitation current, the expected magnetic field sensitivity ( SNR = 1) is 175 µ Oe.…”

Section: Characterisationmentioning

confidence: 99%

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The Scanning TMR Microscope for Biosensor Applications

et al. 2015

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We present a novel tunnel magnetoresistance (TMR) scanning microscope set-up capable of quantitatively imaging the magnetic stray field patterns of micron-sized elements in 3D. By incorporating an Anderson loop measurement circuit for impedance matching, we are able to detect magnetoresistance changes of as little as 0.006%/Oe. By 3D rastering a mounted TMR sensor over our magnetic barcodes, we are able to characterise the complex domain structures by displaying the real component, the amplitude and the phase of the sensor’s impedance. The modular design, incorporating a TMR sensor with an optical microscope, renders this set-up a versatile platform for studying and imaging immobilised magnetic carriers and barcodes currently employed in biosensor platforms, magnetotactic bacteria and other complex magnetic domain structures of micron-sized entities. The quantitative nature of the instrument and its ability to produce vector maps of magnetic stray fields has the potential to provide significant advantages over other commonly used scanning magnetometry techniques.

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Section: Instrument Designsupporting

confidence: 79%

Section: Characterisationmentioning

confidence: 54%

Section: Characterisationmentioning

confidence: 54%

Section: Characterisationmentioning

confidence: 99%

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The Scanning TMR Microscope for Biosensor Applications

et al. 2015

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“…It is applicable to a broader field range than magneto-optical indicator film techniques 6,7 , which are limited by the saturation field of the sensor film. Unlike magneto-resistive sensors 8,9 , Hall probes show excellent linearity without hysteresis and measure a well-defined field component perpendicular to the sensor plane. Furthermore, SHPM enables a low sample-probe distance and therefore a spatial resolution limited by the sensor size only.…”

Section: Introductionmentioning

confidence: 99%

Traceably calibrated scanning Hall probe microscopy at room temperature

Gerken

Solignac

Pakdehi

et al. 2020

J. Sens. Sens. Syst.

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Abstract. Fabrication, characterization and comparison of gold and graphene micro- and nanoscale Hall sensors for room temperature scanning magnetic field microscopy applications are presented. The Hall sensors with active areas from 5 µm down to 50 nm were fabricated by electron-beam lithography. The calibration of the Hall sensors in an external magnetic field revealed a sensitivity of 3.2 mV A−1 T−1 ± 0.3 % for gold and 1615 V A−1 T−1 ± 0.5 % for graphene at room temperature. The gold sensors were fabricated on silicon nitride cantilever chips suitable for integration into commercial scanning probe microscopes, allowing scanning Hall microscopy (SHM) under ambient conditions and controlled sensor–sample distance. The height-dependent stray field distribution of a magnetic scale was characterized using a 5 µm gold Hall sensor. The uncertainty of the entire Hall-sensor-based scanning and data acquisition process was analyzed, allowing traceably calibrated SHM measurements. The measurement results show good agreement with numerical simulations within the uncertainty budget.

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Characterization of Magnetic Nanoparticles Using Magnetic Force Microscopy

Agarwal

2009

Nanotechnologies for the Life Sciences

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15 IntroductionThe aim of this chapter is to provide an overview of the magnetic force microscopy ( MFM ) technique and its application for the characterization of magnetic nanoparticle s ( MNP s). The chapter also serves as a user ' s guide to MFM, without unnecessary repetition of previously published information, and without excessive mathematical detail. The reader is introduced to physical principals of MFM, the properties of MFM probes, probe calibration, methods of MFM detection, and application of MFM for MNPs. The goal is not to provide a detailed overview of MFM and hardware design, as several excellent texts (cited in the references) are available for this purpose. Rather, the special considerations and challenges required for MFM studies of MNPs, especially in biological samples, are highlighted. The chapter concludes with some details of the recent developments and future trends in MFM of MNPs for the life sciences. Development of MFMUnderstanding the nature of magnetism at the nanometer -length scale is of interest from a fundamental perspective, as well as for the development of next generation of MNPs for the life sciences. The study of MNPs involves special challenges since, below a critical dimension, the competition between magnetostatic energy and exchange energy is predicted to suppress magnetic domain formation, leading to single -domain structures. These single -domain MNPs not only possess low magnetization values, as compared to bulk material, but may also have lower coercivity or a superparamagnetic character at temperatures conducive to living systems. Thus, specialized techniques are needed to understand and characterize the magnetic nature of MNPs.

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Quantitative current measurements using scanning magnetoresistance microscopy

Cited by 4 publications

References 10 publications

The Scanning TMR Microscope for Biosensor Applications

The Scanning TMR Microscope for Biosensor Applications

Traceably calibrated scanning Hall probe microscopy at room temperature

Characterization of Magnetic Nanoparticles Using Magnetic Force Microscopy

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