Low-frequency noise in planar Hall effect bridge sensors

Persson, Anders; Bejhed, Rebecca Stjernberg; Nguyen, Hugo; Gunnarsson, Klas; Dalslet, Bjarke Thomas; Østerberg, Frederik Westergaard; Hansen, Mikkel Fougt; Svedlindh, Peter

doi:10.1016/j.sna.2011.09.014

Cited by 25 publications

(25 citation statements)

References 30 publications

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“…This was attributed to instabilities in the flow control, and to slipping phenomena 25 and/or turbulence at the gas inlet. Flicker noise-also known as 1/f noise due to its inverse frequency dependence-is a very common phenomenon, occurring in almost every physical process (from spin-ordering in magnetic materials 26 to highway traffic patterns 27 ). The power spectral density of flicker noise, S 1/f , in electromagnetic systems can be empirically described by the Hooge equation…”

Section: -6mentioning

confidence: 99%

Microplasma source for optogalvanic spectroscopy of nanogram samples

Berglund

Thornell

Persson

2013

Journal of Applied Physics

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The demand for analysis of smaller samples in isotopic ratio measurements of rare isotopes is continuously rising with the development of new applications, particularly in biomedicine. Interesting in this aspect are methods based on optogalvanic spectroscopy, which have been reported to facilitate both 13 C-to-12 C and 14 C-to-12 C ratio measurements with high sensitivity. These methods also facilitate analysis of very small samples, down to the microgram range, which makes them very competitive to other technologies, e.g., accelerator mass spectroscopy. However, there exists a demand for moving beyond the microgram range, especially from regenerative medicine, where samples consist of, e.g., DNA, and, hence, the total sample amount is extremely small. Making optogalvanic spectroscopy of carbon isotopes applicable to such small samples, requires miniaturization of the key component of the system, namely the plasma source, in which the sample is ionized before analysis. In this paper, a novel design of such a microplasma source based on a stripline split-ring resonator is presented and evaluated in a basic optogalvanic spectrometer. The investigations focus on the capability of the plasma source to measure the optogalvanic signal in general, and the effect of different system and device specific parameters on the amplitude and stability of the optogalvanic signal in particular. Different sources of noise and instabilities are identified, and methods of mitigating these issues are discussed. Finally, the ability of the cell to handle analysis of samples down to the nanogram range is investigated, pinpointing the great prospects of stripline split-ring resonators in optogalvanic spectroscopy. V C 2013 AIP Publishing LLC. [http://dx

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Section: -6mentioning

confidence: 99%

Microplasma source for optogalvanic spectroscopy of nanogram samples

Berglund

Thornell

Persson

2013

Journal of Applied Physics

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“…Low-noise signal amplification can significantly improve this as the sensors have a very low intrinsic noise level. 23 For example, the present sensors have a calculated thermal noise on the order of 1 nV under the present measurement conditions. The time domain measurements can also be improved by magnetic and electrical shielding of the set-up and the inclusion of gradiometer-like sensor configurations.…”

Section: A Bead Sizementioning

confidence: 79%

On-chip Brownian relaxation measurements of magnetic nanobeads in the time domain

Østerberg

Rizzi

Hansen

2013

Journal of Applied Physics

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We present and demonstrate a new method for on-chip Brownian relaxation measurements on magnetic nanobeads in the time domain using magnetoresistive sensors. The beads are being magnetized by the sensor self-field arising from the bias current passed through the sensors and thus no external magnetic fields are needed. First, the method is demonstrated on Brownian relaxation measurements of beads with nominal sizes of 40, 80, 130, and 250 nm. The results are found to compare well to those obtained by an already established measurement technique in the frequency domain. Next, we demonstrate the time and frequency domain methods on Brownian relaxation detection of clustering of streptavidin coated magnetic beads in the presence of different concentrations of biotin-conjugated bovine serum albumin and obtain comparable results. In the time domain, a measurement is carried out in less than 30 s, which is about six times faster than in the frequency domain. This substantial reduction of the measurement time allows for continuous monitoring of the bead dynamics vs. time and opens for time-resolved studies, e.g., of binding kinetics. V C 2013 AIP Publishing LLC. [http://dx

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“…Two overlapping frequency ranges were used during the measurements; 125 mHz to 200 Hz and 8 Hz to 12.8 kHz. The noise measurement set-up is described in detail in reference [35].…”

Section: Methodsmentioning

confidence: 99%

“…These employ the off-diagonal terms of the magnetic field-dependent resistivity tensor of an AMR sensor [32,33]. PHE sensors have an intrinsically linear low-field response with small hysteresis, combined with a relatively moderate low-frequency noise as compared to, e.g., GMR and TMR sensors [34,35]. Among magnetoresistive sensors, the closest analogy to PHE sensors are barber pole AMR sensors that share the moderate low-frequency noise [36], but are linearized by barber-pole shaped electrodes on top of the ferromagnetic sensor strip, rotating the current vector in the strip by 45° to its length [37].…”

Section: Fig 1 Dynamic Field Range and Detectivity Of Some Magnetommentioning

confidence: 99%

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Modelling and design of planar Hall effect bridge sensors for low-frequency applications

Persson

Bejhed

Østerberg

et al. 2013

Sensors and Actuators A: Physical

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This is an accepted version of a paper published in Sensors and Actuators A-Physical. This paper has been peer-reviewed but does not include the final publisher proofcorrections or journal pagination.Citation for the published paper: Persson, A., Bejhed, R., Oesterberg, F., Gunnarsson, K., Nguyen, H. et al. (2012) "Modelling and design of planar Hall effect bridge sensors for low-frequency applications" Sensors and Actuators Access to the published version may require subscription. AbstractThe applicability of miniaturized magnetic field sensors is being explored in several areas of magnetic field detection due to their integratability, low mass, and potentially low cost. In this respect, different thin-film technologies, especially those employing magnetoresistance, show great potential, being compatible with batch micro-and nanofabrication techniques. For lowfrequency magnetic field detection, sensors based on the planar Hall effect, especially planar Hall effect bridge (PHEB) sensors, show promising performance given their inherent lowfield linearity, limited hysteresis and moderate noise figure. In this work, the applicability of such PHEB sensors to different areas is investigated. An analytical model is constructed to estimate the performance of an arbitrary PHEB sensor geometry in terms of, e.g., sensitivity and detectivity. The model is valid for an ideal case, e.g., disregarding shape anisotropy effects, and also incorporates some approximations. To validate the results, modelled data was compared to measurements on actual PHEBs and was found to predict the measured values within 13% for the investigated geometries. Subsequently, the model was used to establish a design process for optimizing a PHEB to a particular set of requirements on the bandwidth, detectivity, compliance voltage and amplified signal-to-noise ratio. By applying this design process, the size, sensitivity, resistance, bias current and power consumption of the PHEB can be estimated. The model indicates that PHEBs can be applicable to several different areas within science including satellite attitude determination and magnetic bead detection in labon-a-chip applications, where detectivities down towards 1 nTHz -0.5 at 1 Hz are required, and maybe even magnetic field measurements in scientific space missions and archaeological surveying, where the detectivity has to be less than 100 pTHz -0.5 at 1 Hz.

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Low-frequency noise in planar Hall effect bridge sensors

Cited by 25 publications

References 30 publications

Microplasma source for optogalvanic spectroscopy of nanogram samples

Microplasma source for optogalvanic spectroscopy of nanogram samples

On-chip Brownian relaxation measurements of magnetic nanobeads in the time domain

Modelling and design of planar Hall effect bridge sensors for low-frequency applications

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