Author: Sean Eric BarrettPublisher:
ISBN:
Category :
Languages : en
Pages : 424
Book Description
Nuclear Magnetic Resonance Studies of YBa2̳Cu3̳07̳ in the Superconducting State
Author: Sean Eric BarrettNuclear Magnetic Resonance Studies of the High Temperature Superconductors in the Normal and Superconducting States
Author: Nicholas James CurroPublisher:
ISBN:
Category :
Languages : en
Pages : 418
Book Description
Nuclear Magnetic Resonance Studies of Yttrium Barium Copper Oxide in the Superconducting State
Author: Sean Eric BarrettPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In this thesis we report measurements of the $sp{63}$Cu Knight shift in the superconducting state for the plane (Cu(2)) and chain (Cu(1)) sites in YBa$sb2$Cu$sb3$O$sb7$. We also have measured the temperature and field dependent $sp{63}$Cu(2) nuclear spin relaxation rates ($sp{63}$W1$alpha$) in the superconducting state. Our determination of the $sp{63}$Cu Knight shift below T$sb{rm c}$ compensated for the diamagnetic shielding of our sample by using $sp9$Y NMR as an internal field marker. The $sp9$Y resonance was observed in the superconducting state using the Carr-Purcell-Meiboom-Gill pulse sequence to enhance the signal-to-noise ratio. We have interpreted our Knight shift data within a generalized Bardeen-Cooper-Schrieffer (BCS) pairing theory, and find that a spin-singlet pairing state is strongly favored by these data. The data are consistent with either an orbital s-wave or an orbital d-wave pairing state. While we can fit the Cu(2) data with a strong coupling energy gap, the Cu(1) data require a weak coupling gap. During our measurements of the temperature dependence of the Cu(2) spin-lattice relaxation rates in the superconducting state ($sp{63}$W1$alpha$, where $rmvec Hovert~vert\alpha$), we discovered that the anisotropy ratio $sp{63}$W1a/$sp{63}$W1c, which was essentially independent of temperature in the normal state, drops sharply just below T$sb{rm c}$(77 K $
Nuclear Magnetic Resonance Studies in the Normal and Superconducting States of Some V3X Compounds
Author: Bernard George SilbernagelPublisher:
ISBN:
Category : Nuclear magnetic resonance
Languages : en
Pages : 458
Book Description
Nuclear Magnetic Resonance Studies of High Temperature Superconductors
Author: Krzysztof R. GórnyNuclear Magnetic Resonance Studies of the Effect of Vortices on the High Temperature Superconductor YBa2̳Cu3̳O7̳
Author: Craig Thomas MillingPublisher:
ISBN:
Category :
Languages : en
Pages : 214
Book Description
Nuclear Magnetic Resonance Studies of the Effect of Vortices on the High Temperature Superconductor Yttrium Barium Copper Oxide
Author: Nuclear Magnetic Resonance Studies of the 122 Iron-based Superconductors
Author: Adam Paul DioguardiPublisher:
ISBN: 9781303538254
Category :
Languages : en
Pages :
Book Description
Extensive 75As nuclear magnetic resonance (NMR) studies were conducted on a variety of 122 iron-based superconductors. NMR frequency swept spectra and the spin-lattice relaxation rate (T1−1) were measured in CaFe2As2 as a function of temperature. The temperature dependence of the internal hyperfine field was extracted from the spectra, and T1−1 exhibits an anomalous peak attributed to the glassy freezing of domain walls associated with filamentary superconductivity. The field dependence of T1−1 and subsequent bulk resistivity and magnetization measurements also show signatures of filamentary superconductivity nucleated at antiphase domain walls. Systematic doping-dependent NMR studies were also carried out on Ni- and Co-doped BaFe2As2. In the Ni-doped variant, local magnetic inhomogeneities were observed via field swept NMR spectral analyses, and the doping dependence of the Neel temperature T[N] was confirmed by fits to (T1T)−1 (T). Spectral wipeout and stretched exponential relaxation behavior in the Co-doped variant reveal inhomogeneous behavior and the emergence of a cluster spin glass state. The NMR measurements bring into question the details of the phase transition from coexisting antiferromagnetism and superconductivity to pure superconductivity.
Nuclear Resonance Studies of the Superconducting State of YBa2̳Cu3̳O7̳
Author: Joseph Adam MartindalePublisher:
ISBN:
Category :
Languages : en
Pages : 388
Book Description
Strong Correlation and Superconductivity
Author: Hidetoshi FukuyamaPublisher: Springer Science & Business Media
ISBN: 3642838367
Category : Technology & Engineering
Languages : en
Pages : 409
Book Description
This volume contains the proceedings of the ffiM Japan International Sympo sium on Strong Correlation and Superconductivity, which was held in Keidan ren Guest House at the foot of Mt. Fuji, May 21-25, 1989. The purpose of the Symposium was to provide an opportunity for discus sions on the problem of strong correlation of electrons in the context of high-Tc superconductivity. Sixty-eight scientists were invited from seven countries and forty-three papers were presented in the Symposium. Soon after the discovery ofhigh-Tc superconducting oxides, Professor P. W. Anderson proposed that the essence of high-Tc superconductivity lies in the strong correlation among the electrons in these materials. This proposal has stimulated a wide range of theoretical investigations on this profound and dif ficult problem, which are expected to lead eventually to new concepts describ ing strong electron correlation. In the Symposium, Anderson himself started lively discussions by his talk entitled "Myth and Reality in High-Tc Supercon ductivity", which was followed by various reports on theoretical studies and experimental results. Concise and thoughtful summaries of experiment and theory were given by Professors H. R. Ott and P. A. Lee, respectively. It is our hope that this volume reflects the present status of the research activity on this outstanding problem from the viewpoint of the basic physics and that it will further stimulate the effort to understand these fascinating systems, the high-Tc oxides.