Spin fluctuations in superconducting La{sub 1.85}Sr{sub 0.15}CuO{sub 4}
- Department of Physics, Tohoku University, Sendai 980 (Japan)
- Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
- Institute of Inorganic Synthesis, Faculty of Engineering, Yamanashi University, Kofu 400 (Japan)
Neutron-scattering experiments have been performed to study the dynamic spin properties of La{sub 1.85}Sr{sub 0.15}CuO{sub 4} ({ital T}{sub {ital c}}=33 K) in the temperature range 1.9 K{le}{ital T}{le}150 K and energy range 1.5 meV{le}{omega}{le}20 meV; these span, respectively, {ital T}{sub {ital c}} and the weak-coupling BCS gap energy 2{Delta}{similar_to}10 meV. The width of {ital S}({bold q},{omega}) in momentum space decreases with decreasing temperature at fixed energy as well as with decreasing energy at fixed {ital T}, becoming very sharp at both low {omega} and low temperature. It is found that both in the normal state at {ital T}=35 K and in the superconducting state at {ital T}=10 K the integrated generalized susceptibility {chi}{prime}{prime}({omega})={integral}{sub ({pi},{pi})} d{ital q}{sub 2D}{chi}{prime}{prime}({bold q},{omega}) is constant above {omega}{similar_to}10 meV with an amplitude about three times that in La{sub 1.98}Sr{sub 0.02}CuO{sub 4} and begins to decrease with decreasing {omega} at {omega}{similar_to}10 meV, which corresponds to the BCS superconducting gap energy 2{Delta}. However, we observe nonzero magnetic scattering well below the pseudogap energy at temperatures as low as 2 K. These results are compared with those in La{sub 1.98}Sr{sub 0.02}CuO{sub 4} and YBa{sub 2}Cu{sub 3}O{sub 6.6}.
- Research Organization:
- Brookhaven National Laboratory
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 142619
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 10 Vol. 49; ISSN 0163-1829; ISSN PRBMDO
- Country of Publication:
- United States
- Language:
- English
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