Dependence of noise in magnetic tunnel junction sensors on annealing field and temperature

Liou, Sy‐Hwang; Zhang, Rui; Russek, Stephen E.; Lü, Yuan; Halloran, Sean; Pappas, David P.

doi:10.1063/1.2837659

Cited by 34 publications

(11 citation statements)

References 12 publications

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“…The magnetic noise in this sensor is significantly reduced by our annealing process similar to results presented in Ref. 16. Fig.…”

Section: Fabrication Of Magnetoresistive Sensorsupporting

confidence: 73%

“…The sensor voltage and preamplifier bias are supplied by batteries to minimize noise. The MTJ sensor bridge was annealed at 265°C under a 7 T magnetic field for 15 min in a hydrogen environment which have been demonstrated to reduce the noise level of the MTJs at low frequency [16].…”

Section: Fabrication Of Magnetoresistive Sensormentioning

confidence: 99%

“…The key features of this design are (1) decreasing the noise by the use of a 64 element bridge, (2) reducing the magnetic noise by annealing of MTJ in high magnetic field and a hydrogen environment, [16] and (3) increasing signal by using a external flux-to-field magnetic flux concentrators (MFC).…”

Section: Introductionmentioning

confidence: 99%

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Magnetic Sensors with Picotesla Magnetic Field Sensitivity at Room Temperature

Liou¹

2008

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Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. AbstractHigh sensitivity magnetic sensors will have a significant impact on security, industry, and quality of life. Many of these applications require sensitivities better than 1 nT/Hz 1/2 as well as low cost, small size, low maintenance, and low power consumption. This project is to develop highly sensitive magnetic sensors that fit the goal of the MMSON-07-03 Statement of Need. This need is to develop novel sensors applicable to the diverse detection and discrimination problems of munitions and explosives of concern (MEC) contaminated sites.We present a design of a low power, compact, magnetoresistive sensor. The key features of the design are (1) decreasing the noise by the use of a 64 element bridge, (2) reducing the magnetic noise by annealing of MTJ in high magnetic field and a hydrogen environment, and (3) increasing signal by the use of external low-noise magnetic flux concentrators. The field noise of our prototype magnetic sensor are approximately 1 pT/Hz 1/2 at 1 kHz, 5 pT/Hz 1/2 at 10 Hz, and 50 pT/Hz 1/2 at 1 Hz at room temperature. The magnetic sensor only dissipates 15 mW of power while operating.5 Tables Table 1 The estimated gains of various MFCs at gape of 1 mm Figures Fig. 1 (a) 64 element symmetric configuration (b) 64 element asymmetric configuration Arrows in the graph indicate the reference layer pinning direction.

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“…The magnetic noise in this sensor is significantly reduced by our annealing process similar to results presented in Ref. 16. Fig.…”

Section: Fabrication Of Magnetoresistive Sensorsupporting

confidence: 73%

Section: Fabrication Of Magnetoresistive Sensormentioning

confidence: 99%

See 1 more Smart Citation

Magnetic Sensors with Picotesla Magnetic Field Sensitivity at Room Temperature

Liou¹

2008

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“…The nonmagnetic 1/f noise from the barrier can be substantially reduced by thermal annealing. 12,13 The magnetic 1/f noise is the dominant noise source in MTJs. Reducing the magnetic noise is of importance to improve the field detectivity in MTJ (sensor) devices.…”

mentioning

confidence: 99%

Yoke-shaped MgO-barrier magnetic tunnel junction sensors

Chen

Carroll

Feng

et al. 2012

Applied Physics Letters

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“…It has been shown that low frequency magnetic noise in TMR sensors can be reduced by the application of a hard axis bias field 6 and annealing in a high magnetic field. 9 In this work, we developed a TMR sensor with perpendicular anisotropy in the sensing layer and we used the voltage-induced anisotropy modulation as an efficient means of reducing magnetic noise.…”

mentioning

confidence: 99%