Low aspect ratio micron size tunnel magnetoresistance sensors with permanent magnet biasing integrated in the top lead

Chaves, R. C.; Cardoso, Susana; Ferreira, Ricardo; Freitas, P. P.

doi:10.1063/1.3537926

Cited by 33 publications

(20 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…On the other hand, the adoption of single MTJ sensors with an increased A allows a lower noise level according to (1). However, increasing A requires the use of linearization strategies, such as permanent magnets (PMs) [11] or the use of a soft pinned sensing layer [12], [13]. The main advantage of a single sensor is the possibility to introduce magnetic flux guides (MFGs) to increase the sensor sensitivity, yielding a detectivity improvement.…”

Section: Introductionmentioning

confidence: 99%

Strategies for pTesla Field Detection Using Magnetoresistive Sensors With a Soft Pinned Sensing Layer

et al. 2015

View full text Add to dashboard Cite

The detection of low-intensity and low-frequency signals requires magnetic sensors with enhanced sensitivity, low noise levels, and improved field detection at low operating frequencies. Two strategies to improve the detectivity levels of devices based on tunnel magnetoresistive sensors are demonstrated: 1) a large number of sensors connected in series or 2) an individual sensor with a large sensing area and integrated magnetic flux guides. State-of-the-art MgO-based magnetic tunnel junctions with a soft pinned sensing layer were used in this paper. For 952 sensors in series a sensitivity of 29.3%/mT and a detection level of 455 pT/Hz 1/2 were obtained at 100 Hz, whereas the integration of magnetic flux guides in a single sensor yielded a sensitivity of 138.3%/mT and a detection level of 576 pT/Hz 1/2 at the same frequency. These two strategies imply a large device footprint, being suitable when a high spatial resolution is not an application requirement.

show abstract

Section: Introductionmentioning

confidence: 99%

Strategies for pTesla Field Detection Using Magnetoresistive Sensors With a Soft Pinned Sensing Layer

et al. 2015

View full text Add to dashboard Cite

show abstract

“…However, increasing the width of the sensor above a few microns results in a strong decrease of the demagnetizing field which soon becomes too weak to be noticeable and shape anisotropy alone can no longer provide linear transfer curves [8], [9]. In this range, the linearization of the sensors relies on methods such as the inclusion of permanent magnets in the vicinity of the magnetic tunnel junction (MTJ) pillars to provide an orthogonal biasing field [10], [11] or the use of thin CoFeB layers [12] . Here W, X, Y and Z represent thicknesses which can be changed in order to tune the linear range of the final devices.…”

Section: Introductionmentioning

confidence: 99%

Large Area and Low Aspect Ratio Linear Magnetic Tunnel Junctions With a Soft-Pinned Sensing Layer

et al. 2012

Self Cite

View full text Add to dashboard Cite

Large area MTJs with linear response and very larger sensitivities are needed to fulfill the requirements for the detection of pT/Hz magnetic fields at low frequency and room temperature. MTJ stacks with soft-pinned sensing layers have been developed and the stack was optimized, providing a tunable soft-pinning field over a large range of values. Sensitivities corresponding to resistance changes of up to 7%/Oe are obtained in patterned MTJs with areas of 20 20 m starting from films with high sensitivity soft-pinned layers made from 3.0 Co Fe B /0.21 Ta/8.0 Ni Fe /8.0 Ir Mn . Index Terms-Linear magnetic tunnel junctions, magnetoresistive sensors, 1/f noise.

show abstract

“…17a), avoiding an extra lithography step. This strategy was successfully validated in reference [78]. To ensure the best field uniformity, dimensions should be considerably larger than the sensing layer size.…”

Section: -P9mentioning

confidence: 99%

“…external magnetic field biasing created on-chip (e.g., using integrated permanent magnets or current line) [77,78] (Fig. 12c, Sect.…”

Section: -P7mentioning

confidence: 99%

Linearization strategies for high sensitivity magnetoresistive sensors

Silva

Leitao

Valadeiro

et al. 2015

Eur. Phys. J. Appl. Phys.

102

View full text Add to dashboard Cite

Abstract. Ultrasensitive magnetic field sensors envisaged for applications on biomedical imaging require the detection of low-intensity and low-frequency signals. Therefore linear magnetic sensors with enhanced sensitivity low noise levels and improved field detection at low operating frequencies are necessary. Suitable devices can be designed using magnetoresistive sensors, with room temperature operation, adjustable detected field range, CMOS compatibility and cost-effective production. The advent of spintronics set the path to the technological revolution boosted by the storage industry, in particular by the development of read heads using magnetoresistive devices. New multilayered structures were engineered to yield devices with linear output. We present a detailed study of the key factors influencing MR sensor performance (materials, geometries and layout strategies) with focus on different linearization strategies available. Furthermore strategies to improve sensor detection levels are also addressed with best reported values of ∼40 pT/ √ Hz at 30 Hz, representing a step forward the low field detection at room temperature.

show abstract

Low aspect ratio micron size tunnel magnetoresistance sensors with permanent magnet biasing integrated in the top lead

Cited by 33 publications

References 17 publications

Strategies for pTesla Field Detection Using Magnetoresistive Sensors With a Soft Pinned Sensing Layer

Strategies for pTesla Field Detection Using Magnetoresistive Sensors With a Soft Pinned Sensing Layer

Large Area and Low Aspect Ratio Linear Magnetic Tunnel Junctions With a Soft-Pinned Sensing Layer

Linearization strategies for high sensitivity magnetoresistive sensors

Contact Info

Product

Resources

About