1. EPR OF QUASIPARTICLES BY FLUCTUATIONS OF COOPER PAIRS Jan Stankowski Institute of Molecular Physics, Polish Academy of Sciences Kazimierz Dolny 2005

2. TRANSPORT PHENOMENA Microwave Absorption (MA) was discovered in HTSC as a zero field „EPR” line MA results from by Cooper pair breaking when fluxes penetrate through a Josephson weak links (JWL) Dynamics of the field dependent MA implies, that flux flow, its pinning and creep by: 1 o defects and 2 o weak contacts give the nonresonant AC dissipation. AIM OF THIS WORK Electron paramagnetic resonance - EPR in quasiparticles system and sharp AC anomaly in field B EPR (f) close to g 0

3. 00 VORTEX

4. CURRENT INDUCED VORTEX MOTION CAUSE QP FLUCTUATIONS V ~ J x Ф

5. CHEMICAL DEFECTS POTENTIAL IS B INDEPENDENT JWC POTENTIAL IS PERIODICALY B DEPENDENT

6. BB  = n  0 +  0  = n  0  = n  0 +  0 U SC WJL

7. ANALYSIS OF AC ABSORPTION Vortex motion (VM) model by Coffey and Clem VM resistivity is due to formation of quasiparticles (QP) In two-liquid model: n=n QP + 2n SC

8. DISTRIBUTION OF CPs AND NORMAL ELECTRONS (QPs) QP CP

9. MAGNETIC FIELD DEPENDENT AC ABSORPTION IN SUPERCONDUCTORS

10. ZERO FIELD ABSORPTION LINE FOR JWL

11. HTSC RESISTIVITY VS. MAGNETIC FIELD T=80 K T=85 K E. Silva et al., Int. J. of Modern Physics B, 17, 922 (2003)

12. VORTEX MOTION HYSTERESIS LOOPS AC ABSORPTION DIFFERENTIAL MMMA SIGNAL

13. VORTEX MOTION HYSTERESIS LOOP LC CIRCUIT FOR 22 MHz Magnetic field modulation (50Hz ) UU

14. MAGNETIC ANOMALY IN SLIGHTLY DOPED FULLERENE

15. TWO PARAMAGNETIC CENTERS

16. AMPLITUDE I’ i OF THE EPR SIGNAL IN C 60 :Rb

17. SPIN EFFECT IN TRANSPORT PHENOMENA - EPR OF QP in VMHL - BLOCH two coil EPR DETECTION - EPR in MICROWAVE IMPEDANCE

18. sample LC OSCILLATING CIRCUIT (22MHz)

19. JOSEPHSON HYSTERESIS LOOP IN LC CIRCUIT FOR 22 MHz 50Hz B field modulation UU

20. BLOCH NMR HEAD Magnetic field Generating coil Receiving coil 15 MHz

21. AC INDUCTION IN BLOCH TWO COIL METHOD YBCO signal DPPH strong sample

22. NON-LINEAR VORTEX TO THE MAGNETIC FIELD CuO 2 plane Magnetic Field

23. AC DISSIPATION IN YBCO AT 21 GHz, from E. SILVA J. Low Temp. Phys., 131, 871 (2003)

24. COMPUTER EXTRACTION OF THE SPIN SIGNAL FROM AC DISSIPATION

25. LOW FREQUENCE LIMIT g -factor close to 2 HIGH FREQUENCE g -factor for localized state: C 60 1- ion in fullerene and Cu 2+ - ion in YBCO

26. CONCLUSIONS 1. FLUX MOTION GENERATING QP LEADS TO NONRESONANT AC MAGNETIC FIELD DISSIPATION 2. EPR OF NORMAL ELECTRONS (QP) IS RELATED TO LOCALIZED SPIN STATE ON PARAMAGNETIC CENTERS g  g 0 SHOWING THAT CONDUCTING CARRIERS ARE STRONGLY CORRELATED ELECTRONS

27. Low field study of EPR and paramagnetic fluctuation can be used to study interaction between local pairs (boson liquid) and quasiparticles (quasi Fermi liquid). T.Domański, K.I.Wysokiński, Phys.Rev. B 66,064517-1 (2002)

28. COLLABORATION R. Micnas - theory advisor UAM IFM PAN J. Martinek - theory of nonresonant MA W. Kempiński - MMMA experiments L. Piekara-Sady - fullerenes J. Grembowski - low freq.exp. W. Bednarski - comuter expert

29. THANKS FOR ATTENTION

30. Institute of Molecular Physics, Polish Academy of Sciences e-mail: janstank@ifmpan.poznan.pl