Data Analysis of Pulse Measurements

1. Data Analysis of Pulse Measurements Sample 24-19

2. Pulse Diagrams On axis We can clearly see the critical current evolution with field.The shape of the boundaries does not evolve significantly with field

3. Pulse Diagrams Fitting On axis

4. Pulse Diagrams 45 degrees Shape variation is much more important, may be due to lack of resolution in diagrams

5. Pulse Diagrams Fitting 45 degrees

6. Pulse Diagrams 60 degrees, no amplifier Right part of the diagrams is “noisy”

7. Pulse Diagrams 60 degrees, amplifier Similar to 0deg case, shorter time scale thanks to amplifier

8. Pulse Diagrams 60 degrees

9. Pulse Diagrams Fitting 60 degrees

10. B=0T comparison

11. Comparison of angles for same field B=0.04T

12. FittingB=0.04T

13. BoundariesB=0.08T

14. FittingB=0.08T

15. BoundariesB=0.12T

16. FittingB=0.12T

17. Comparison of angles for same axis field Bax=0.02T

18. Fitting Bax=0.02T

19. Boundaries Bax=0.04T

20. Fitting Bax=0.04T

21. Boundaries Bax=0.06T

22. Fitting Bax=0.06T

23. Macrospintheory • J.Z Sun, PRB62, Spin current interaction with a monodomain magnetic body A [Hz/V] characterizes dynamic evolution

24. Macrospintheory Therefore Should be in accordance with static diagram According to J.Z. Sun’s paper, we would have

25. Static Phase Diagram I=0.03+0.033B I=-0.018-0.173B I=0.07+0.1B I=-0.007-0.0375B Implies Hk=0.1T, very close to value extracted from hysteresys loop

26. Critical current behaviorOn axis case Implies Hk=0.285T, expected value would be 0.1T

27. 45 degrees Phase Diagram I=-0.003-0.032B I=-0.027+ 0.243B I=0.012-0.173B I=-0.007+ 0.023B Implies Hk=0.1T, very close to value extracted from hysteresys loop

28. Critical current behavior45 degrees case 45deg pulse diagrams lack resolution, this is probably one of the main causes why the data looks so noisy. Hk~1.5T

29. Critical current behavior60 degrees case V=-0.317-0.012B V=-0.34-0.4B Implies Hk=0.85T or 26T, way off from expected 0.1T Unfortunately we do not have a 60deg phase diagram

30. Fitting ParametersTheory

31. Finding Initial Angle Minimizing energy Thermal fluctuations M According to fluctuation-dissipation theorem on 10ps timescale Very low compared to tilted field effect

32. Fitting ParametersTheory Low angle (0-5deg) case

33. Low Angle(2deg),Fitting Parameter A We seed P2 at 10 (equivalent to assuming Hk=0.1), and it evolves towards 3.5 (equivalent to Hk=0.28) as in previous critical current analysis

34. Low Angle(2deg),Fitting Parameter B Theoretical formula does not fit at all

35. 45deg Fitting Parameter A Resulting Hk is 0.5T, fitting is reasonnable

36. 45deg Fitting Parameter B Resulting Hk is 2.5T, for lower Hk, fitting gets much worse

37. 60deg Fitting Parameter ANo Amplifier Resulting Hk is 0.3T, good agreement but few points

38. 60deg Fitting Parameter BNo Amplifier Resulting Hk is 0.5T

39. 60deg Fitting Parameter AAmplifier Resulting Hk is 0.8T

40. 60deg Fitting Parameter BAmplifier Resulting Hk is 1.7T

41. Conclusion • Evolution of A with field. Meaning lower “coercitive field” also accelerate current dynamics.Less effective field, less “damping”. • Evolution of B shows that at an angle, A does not control entirely the change in critical current (B/A) • Axis field seems to have a dominant effect on critical current and dynamics, as boundaries/fits with same axis field are much more similar than those with same overall field strength

42. Precessional studies • Precessional studies: Hk=0.1T=> Frequency at 0 Field. Field precision is 0.01T =>Precession period of up to ~3ns • Maximum achievable field angle: 30deg angle would provide for 600ps period. However, anisotropy field decreases as cos( )=>max workable field angle is lower • Show precessional switching by positive pulse switching • Double pulse experiment

43. Precession Frequency P->AP, 2 magnonsHcoerc=0.05,Hdip=0.05

44. Precession Frequency, LLG method

45. Precession Frequency AP->P, 2 magnons

46. Precession Frequency AP->P, LLG