Presentation is loading. Please wait.

Presentation is loading. Please wait.

1 High Sensitivity Magnetic Field Sensor Technology overview David P. Pappas National Institute of Standards & Technology Boulder, CO.

Similar presentations


Presentation on theme: "1 High Sensitivity Magnetic Field Sensor Technology overview David P. Pappas National Institute of Standards & Technology Boulder, CO."— Presentation transcript:

1 1 High Sensitivity Magnetic Field Sensor Technology overview David P. Pappas National Institute of Standards & Technology Boulder, CO

2 2 Market analysis - magnetic sensors 2005 Revenue Worldwide - $947M Growth rate 9.4% Type Application “World Magnetic Sensor Components and Modules/Sub-systems Markets” Frost & Sullivan, (2005)

3 3 Outline High sensitivity applications Noise & signal measurement Description of various types of sensors Addition of flux concentrators Summary

4 4 Applications Health Care Geophysical Astronomical Archeology Non-destructive evaluation (NDE) Data storage North Caroline Department of Cultural Resources “Queen Anne’s Revenge” shipwreck site Beufort, NC Mars Global Explorer (1998) Magnetic RAM SI units Magneto-encephalography Magneto- Cardiography “Biomagnetism using SQUIDs: Status and Perspectives” Sternickel, Braginski, Supercond. Sci. Technol. 19 S160–S171 (2006). Bio-magnetic tag detection Frietas, ferreira, Cardoso, Cardoso J. Phys.: Condens. Mater 19, (2007) JPL - SAC-C mission Nov. (2000)

5 5 SI - Le Système International d’Unitès I (A) r (m) “Magnetic field intensity”: H-field  A/m  B = flux density = “Magnetic induction” field Frequency What do we measure? Use  0 = permeability of free space B =  0 H B-field  tesla (T) kg/(As 2 ) A  = B  A H = ~0.1 A/m B = 2  T e.g. 1 1 m

6 6 B-field Ranges & Frequencies Adapted from “Magnetic Sensors and Magnetometers”, P. Ripka, Artech, (2001) F.L. Fagaly Magnetics Business & Technology Summer fT 1 nT  , Frequency (Hz) Magnetic field Range 1 pT Geophysical Industrial Magnetic Anomaly Magneto- cardiography Magneto- encephalography 1 fT , Frequency (Hz) B-field 1 pT Geophysical Industrial/NDE Magnetic Anomaly Magneto-cardiography Magneto- encephalography 1 nT 1 gauss  T ~ Earth’s B-field 1 mT effects 1  T 1 1 m

7 7 B-fields… Induce voltages Affect scattering of electrons in matter Change phase of currents flowing in superconductors Create energy level splittings in atoms => Use these effects to build a toolbox for field detection in important applications Technologies

8 8 Magnetometer technologies Induction  Search Coil  Fluxgate  Giant magneto-impedance Scattering  Anisotropic magneto-resistive (AMR)  Spintronic – Giant MR, Tunneling MR, Spin Xtor…  Hall Effect  Magneto-optical Superconducting  SQUIDS Spin Resonance  Proton, electron State

9 9 State measurement Low noise excitation source -  Voltage, current, light, … Sense state with detector Flux feedback is typical  Linearize  Dynamic Range  Complicated  Limits slew rate & bandwidth B ext  BfBf B S Noise S

10 10 Noise metrology Magnetically shielded container (or room) Low noise preamplifiers Spectrum analyzer – P = V 2 /Hz  field noise =  power / sensitivity State Measurement Low T C SQUID magnetometer (w/gradiometer) Hz ,000 10, ,000 f T/  Hz Benchmarks 1/f White Units: Preamp

11 11 Benchmark properties: SQUID State variableV, f, etc B-field measurementVector/scalar 1 Hz T/  Hz Operating TCryogenic/RT Volume of sense elementcm 3 – mm 3 Power – form factorLine/Battery

12 12 Superconducting Quantum Interference Devices ILIL IRIR I Tunnel Junctions B Left-Right phase shifted by B  Signal PU loop Superconductor

13 13 Pickup loops for SQUIDS One loop: measure B Z Two opposing loops:  dB Z /dz (1 st order gradiometer)  Good noise rejection Opposing gradiometers:  dB Z 2 /dz 2 (2 nd order gradiometer)  High noise rejection NSNS SQUID specs Z

14 14 SQUID Magnetometer “The SQUID Handbook,” Clarke & Braginski, Wiley-VCH 2004 Commercial: 10 – 100’s k$ Resonance Discrete components Integrated Systems State variable Voltage (10’s  V) B-fieldVector, gradients 1 Hz ~10 fT/  Hz Low T C Operating Tcryogenic Volume~ 1 cm 3 coil PowerLine

15 15 Real time magneto-cardiography with SQUID magnetometer Oh, et. al JKPS (2007) ~60 pT Benchmark

16 16 Resonance magnetometers Nuclear spin resonance  Protons water, methanol, kerosene Overhauser effect:  He 3, Tempone Electron spin resonance  He 4,Alkali metals (Na, K, Rb) B ext f  B ext Proton

17 17 Proton magnetometer Commercial: 5 k$ Kerosene cell Toroidal excitation & pickup Olsen, et. al (1976) From Ripka, (2001) e - spin State variableFrequency ~ kHz B-fieldScalar 1 Hz sources ~10 pT/  Hz depolarization Operating T-20 => 50 o C Volume1 cm 3 cell PowerBattery

18 18 Electron spin magnetometers Vapor cell Photodetector B ext RF Coils /4 Filter Laser Budker, Romalis, Nature Physics, 3(4), (2007) He4

19 19 He 4 e - -spin magnetometer JPL - SAC-C mission Nov. (2000) Smith, et al (1991) from Ripka (2001) CSAM State variableFrequency ~ MHz B-fieldvector/scalar 1 Hz 1 pT/  Hz Operating Tambient Volume~10 cm 3 cell Powerbattery

20 20 e - -spin magnetometer Chip scale atomic magnetometer P. D. D. Schwindt, et al. APL 90, (2007). Rb metal vapor Optimized for low power Very small form factor 4.5 mm SERF State variableFrequency B-fieldScalar 1 Hz 5 pT/  Hz Operating T110 o C Volume20 mm 3 PowerSmall battery

21 21 e - -spin magnetometer Spin-exchange relaxation free Kominis, et. al, Nature 422, 596 (2003) K metal vapor Low field, high density of atoms Line narrowing effect All-optical excitation & pickup =>Optimized for high sensitivity Solid state State variableFrequency B-fieldVector < 100 nT 1 Hz < 1 fT/  Hz Operating T180 o C Volume~ 3 cm 3 Powerline

22 22 Solid state magnetometers Inductive  Fluxgate  Giant magneto-impedance Magneto-resistive  AMR – Anisotropic MR Spintronic  GMR – Giant MR  TMR – Tunneling MR Disruptive technologies  Hybrid superconductor/solid state  Magneto-striction

23 23 Fluxgate M H B ext H mod (f) M State variableInductive 2f B-fieldVector 1 Hz sources <10 pT/  Hz Magnetic Johnson Perming Operating TRT Volume1 cm 3 Powerbattery “Magnetic Sensors and Magnetometers” P. Ripka, Artech, 2001 Commercial: ~1 k$ Pickup(2f) Drive(f) FG innov.

24 24 Innovations in Fluxgate technology Apply current in core Single domain rotation 100 fT/  1 Hz Circumferential Magnetization I M Planar fabrication 80 pT/  1 Hz Micro-fluxgates Koch, Rosen, APL 78(13) 1897 (2001) Kawahito S., IEEE J. Solid State Circuits 34(12), 1843 (1999) GMI

25 25 Giant Magneto-impedance (GMI) “Giant magneto-impedance and its applications” Tannous C., Gieraltowski, Jour Mat. Sci: Mater. in Electronics, V15(3) pp (2004) Magnetic amorphous wire I ac M CoFeSiB frequency external field   Enhanced skin effect in magnetic wire GMI spec.

26 26 GMI specifications Commercial: ~100 $ MR State MHz B-fieldVector 1 Hz sources ~3 nT/  Hz 1/f mag noise Temp fluct. M Johnson Perming Operating TRT Volume0.01 mm 3 wire PowerBatter

27 27 “Thin Film Magneto-resistive Sensors S. Tumanski, IOP (2001). Magneto-resistive (MR) sensors AMR - Anisotropic MR  Single ferromagnetic film NiFe  2% change in resistance Spintronic:  GMR – Metal spacer 60%  R/R min Co/Cu/Co Parkin, APL (1991)  TMR – Insulator spacer 472%  R/R min at R.T. CoFeB/MgO/CoFeB Hayakawa, APL (2006) I M FM NM FM * * * * hdd

28 28 MR Sensors – spatial resolution 256 element AMR linear array Thermally balanced bridges High speed magnetic tape imaging – forensics, archival NDE imaging Cassette Tape – forensic analysis 4 mm 45 mm erase head stop event write head stop event da Silva, et al., subm. RSI (2007) Current flow in VLSI RAM w/short 2 cm -I y +I x -I x +I y 4 mm V+ V- I- 16  m x 256 I+ BARC.

29 29 MR biomolecular recognition 1.Nano-scale magnetic labels that attach to target 2.GMR arrays with probe 3.Probes attach to targets  Need very sensitive magnetic detector arrays  Goal: high accuracy chemical assays Device Applications Using SDT, Tondra et. al Springer Lecture Notes in Physics, V593, (2002) “BARC” Bead Array Counter MR sens.

30 30 MR as low field sensors AMR Large area films GMR Small sensors Commercial: ~ $ 2 Unshielded sensors 2 shielded Flux concentrators TMR “Low frequency picotesla field detection…” Chavez, et. al, APL 91, (2007). F.C. State variableResistance B-fieldVector 1 Hz sources ~200 pT/  Hz 1/f mag noise Temp fluct. M Johnson/Shot Perming Operating TRT Volume0.001 mm 3 film Powerbattery

31 31 The joy of flux concentrators B ext a Need: Soft ferromagnet High M =  No hysterisis  Gain up to ~50  No increase in noise  Increase in form factor 2 cm Noise TMR with F.C.

32 32 Spectral noise measurements Hall FC without flux concentrator with external flux concentrator Stutzke, Russek, Pappas, and Tondra, J. Appl. Phys. 97, 10Q107 (2005) Yuan, Halloran, da Silva, Pappas, J. Appl. Phys. submitted (2007) 1 p 1 n 1 

33 33 Integrated Hall sensors with flux concentrators “Bridging the gap between AMR, GMR and Hall Magnetic sensors Popovic, et. al, PROC. 23rd MIEL, V1, NIŠ, YUGOSLAVIA, MAY, 2002 Hall spec. 1Hz (nT/  Hz) White noise (f> 100 Hz) (nT/  Hz) Hall with no flux concentrators * Only internal flux concentrators30030 With both internal and external flux concentrators 303 Internal flux concentrators Hall element

34 34 Hall Effect specifications State variableVoltage B-fieldVector 1 Hz 300 nT/  Hz 30 nT/  Hz w/FC’s Operating TRT Form Factor0.001 mm 3 chip Powerbattery Commercial: ~$ 0.1  1 Applications Keyboard switches Brushless DC motors Tachometers Flowmeters  InAs thin film I V Disruptive - hybrid B

35 35 Disruptive technologies? Superconducting flux concentrator State variableGMR voltage B-fieldVector 1 Hz 32 fT/  Hz Operating Tcryogenic Volume0.1 cm 3 PowerBattery Field Gain YBCO ~ 100 Nb ~ 500 Hybrid S.C./GMR “…An Alternative to SQUIDs” Pannetier, et. al, IEEE Trans SuperCond 15(2), 892 (2005) ME

36 36 Magneto-electric Disruptive No power required Two terminal device High impedance output State variablePiezo voltage B-fieldVector 1 Hz sources 1 nT/  Hz pyro/static Operating T -40 to 150  C Volume1 mm 3 Power0 Dong, Zhai, Xin, Li, Viehland APL V86, (2005). Magnetostrictive + piezo-electric multilayer Terfenol-D H PMN-PT V ME MO

37 37 Magneto-optic State variableLight intensity B-fieldVector 1 kHz 1.4 pT/  Hz Operating Tambient Volume1 cm 3 Powerline Mirror-coated iron garnet Magnetometer head Ferrite Flux Concentrators Light polarization changes in garnet Rotation  B-field (Faraday effect) Sensed with interferometer Fiber- optic Deeter, et. al Electronics Letters, V29(11), p 993 (1993). Youber, Pinassaud, Sensors and Actuators A129, 126 (2006). Disruptive Light not affected by B Remote sensors High speed Imaging capability (light) NDE Spintronic B

38 38 More spintronic sensors Extraordinary MR (EMR)  Hall effect with metal impurity Based on 10 6 MR in van der Pauw disks  Non-magnetic materials   Mesoscopic device   R/R ~ 35% in field Replacement for GMR in hdds?  220% TMR in 2004 … Au InSb B Semiconductor Au impurity “Magnetic Field Nanosensors, Solin, Scientific American V291, 71 (2004) 300 nm V I

39 39 Other disruptive technologies Magneto-strictive delay lines Spintronics:  CMR  Spin-FET – tunnel junctions  Spin-FET – nanowires - APL (2007) concl

40 40 SensorB pt/  1 Hz VolumePower SQUIDv.011 cm 3 Line Protons11 cm 3 battery e - He 4 /CSAM/SERF s/s/v1 / 5 /.001mm 3 – cm 3 Battery-line Fluxgatev101 cm 3 battery GMIv mm 3 battery MRv mm 3 battery Hybrid GMR/SCv cm 3 battery Hallv30, mm 3 battery MEv10001 mm 3 0 Magneto-opticv1 cm 3 line Compilation Trend: Noise increases as Volume decreases

41 41 Trend of volume vs. noise Examples:  AMR Large arrays of elements, good magnetic properties make up for lower noise  Flux concentrators Increase volume  reduced noise floor  Fluxgate magnetometers - S n  T  '' /  Koch – increase volume and decrease loss in material “Fundamental limits…” Koch et al, APL V75, 3862 (1999) Compare sensors based on volumetric energy resolution Energy resolution  Noise Power  Active magnetic volume D. Robbes / Sensors and Actuators A 129 (2006) 86–93 SQUIDS & SERF technique lead, hybrd GMR/S.C. coming up

42 42 Conclusions High sensitivity magnetometers research very active Many advances to be made in conventional devices Potentially disruptive technologies Move to smaller, lower power, nano-fabrication Evalute high sensitivity against many other parameteters:  Spatial resolution, power, vector.. Ackn.

43 43 Acknowledgements Steve Russek Bill Egelhoff John Unguris Mike Donahue John Kitching Fabio da Silva Sean Halloran Lu Yuan


Download ppt "1 High Sensitivity Magnetic Field Sensor Technology overview David P. Pappas National Institute of Standards & Technology Boulder, CO."

Similar presentations


Ads by Google