Coexistence of superconductivity and spin density wave orderings in Bechgaard and Fabre salts

2002 ◽  
Vol 12 (9) ◽  
pp. 197-200
Author(s):  
C. Pasquier ◽  
P. Auban-Senzier ◽  
T. Vuletic ◽  
S. Tomic ◽  
M. Heritier ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Spin Density ◽  
Critical Field ◽  
Density Wave ◽  
Spin Density Wave ◽  
Upper Critical Field ◽  
Small Range ◽  
Zero Field ◽  
Pressure Independent ◽  
Two Phases

In a small range of pressure, superconductivity (SC) and Spin Density Wave (SDW) states are shown to coexist in the Bechgaard salt (TMTSF)2PF6 and the Fabre salt (TMTTF)2BF4. In (TMTSF)2PF6, a precise investigation of the (P,T) phase diagram has led us to demonstrate the coexistence of the two phases with a superconducting critical temperature which is pressure independent while the critical current at zero field is strongly depressed as the pressure is decreased. In (TMTTF)2BF4, using non-linear transport measurements, we present the signature of the presence of 1D superconducting filaments in a small range of pressure. We also investigate the compound under a magnetic field applied along the c*-axis: the upper critical field is more or less pressure independent and is about 2 Tesla (at zero temperature). We suggest that such a high critical field is compatible with the penetration of the magnetic field in the insulating regions of the compound in a similar way of Josephson vortices in layered superconductors.

Magnetic-field behavior of the spin-density-wave state in (TMTSF)2AsF6

1995 ◽  
Vol 52 (22) ◽  
pp. 15983-15991 ◽  
Author(s):  
J. L. Musfeldt ◽  
M. Poirier ◽  
P. Batail ◽  
C. Lenoir
Keyword(s):  
Magnetic Field ◽  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Wave State ◽  
Field Behavior

COLLECTIVE FIELD THEORY TO MAGNETIC-FIELD-INDUCED SPIN-DENSITY-WAVE-STATE IN BECHGAARD SALTS, (TMTSF)2X

1993 ◽  
Vol 07 (19) ◽  
pp. 3415-3421 ◽  
Author(s):  
ALEXANDRE S. ROZHAVSKY
Keyword(s):  
Magnetic Field ◽  
Spin Density ◽  
Chemical Potential ◽  
Density Wave ◽  
Spin Density Wave ◽  
Hall Conductivity ◽  
Chiral Anomaly ◽  
Threshold Field ◽  
Wave State ◽  
Extended States

A field description of spin-density-wave (SDW) in a quasi-two-dimensional metal with open Fermi surface in magnetic field, is proposed. The SDW transition temperature, T c (H), and the Hall conductivity σxy, are calculated. The dependence T c (H) is found to be different from that of the Bardeen-Cooper-Schrieffer model, in particular, a threshold field, H c , found its natural explanation. It is proved that the quantized Hall conductivity arises from the chiral anomaly terms in the effective action provided there is pinning of chemical potential in the gap of extended states.

High magnetic field NMR investigation of the spin density wave phase of TMTSF2PF6

2002 ◽  
Vol 12 (9) ◽  
pp. 389-389
Author(s):  
W. G. Clark ◽  
F. Zamborsky ◽  
B. Alavi ◽  
P. Vonlanthen ◽  
W. Moulton ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Proton Relaxation ◽  
High Magnetic Fields ◽  
Organic Conductor ◽  
First Order ◽  
The Magnetic Field ◽  
Very High

We report proton NMR measurements of the effect of very high magnetic fields up to 44.7 T (1.9 GHz) on the spin density wave (SDW) transition of the organic conductor TMTSF2PF6. Up to 1.8 GHz, no effect of critical slowing close to the transition is seen on the proton relaxation rate (1/T1), which is determined by the SDW fluctuations associated with the phase transition at the NMR frequency. Thus, the correlation time for such fluctuations is less than $1O^{-10}$s. A possible explanation for the absence of longer correlation times is that the transition is weakly first order, so that the full critical divergence is never achieved. The measurements also show a dependence of the transition temperature on the orientation of the magnetic field and a quadratic dependence on its magnitude that agrees with earlier transport measurements at lower fields. The UCLA part of this work was supported by NSF Grant DMR-0072524.

Temperature and magnetic field dependences of rapid oscillations in field induced spin-density-wave phase for (TMTSF)2ClO4

1997 ◽  
Vol 86 (1-3) ◽  
pp. 1909-1910 ◽  
Author(s):  
S. Uji ◽  
T. Terashima ◽  
H. Aoki ◽  
J.S. Brooks ◽  
M. Tokumoto ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Wave Phase

Quantum Hall Effect and Rapid Oscillations in (Tmtsf)2Pf6 under Pressure

1989 ◽  
Vol 173 ◽  
Author(s):  
S. T. Hannahs ◽  
J. S. Brooks ◽  
W. Kang ◽  
P. M. Chaikin ◽  
L. Y. Chiang ◽  
...  
Keyword(s):  
Spin Density ◽  
Quantum Hall Effect ◽  
Density Wave ◽  
Quantum Hall ◽  
Spin Density Wave ◽  
Zero Field ◽  
Conducting Plane ◽  
The Standard Model ◽  
Longitudinal Resistivity ◽  
Good Agreement

ABSTRACTWe present magnetotransport data and the phase diagram derived from them for (TMTSF)2PF6 under sufficient pressure that the zero field Spin Density Wave (SDW) is suppressed and the material is superconducting. Application of a large magnetic field perpendicular to the conducting plane then leads to the cascade of Field Induced Spin Density Wave (FISDW) transitions. The transitions are in good agreement with the Standard model for these transitions and in contrast to the more complicated behavior seen in the ClO4 salt. In addition Hall and longitudinal resistivity indicates a behavior much closer to that observed in conventional Quantum Hall devices than in the ClO4 salt or previous studies of PF6. We do observe the “rapid” Schubnikov de Haas like oscillations in magnetoresistance at high field similar to those seen in ClO4, even though in the present case there is no evidence for anion ordering as some theories would require.

Spin-Density-Wave Transitions in a Magnetic Field

1986 ◽  
Vol 56 (9) ◽  
pp. 972-975 ◽  
Author(s):  
J. F. Kwak ◽  
J. E. Schirber ◽  
P. M. Chaikin ◽  
J. M. Williams ◽  
H. -H. Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave
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