Inter-plane Coupling and Spin Gap - an NMR/NQR Look on Typical Properties of High-Temperature Superconductors *
نویسنده
چکیده
The paper discusses some N Q R / N M R studies performed on Y B a C u O superconductors at the University of Zürich. In particular, we review studies performed in Y 2 B a 4 C u 7 0 1 5 by measuring various planar Cu N Q R / N M R parameters: the spin-lattice relaxation time, the Knight shift and the indirect component of the Gaussian contr ibution to the spin-spin relaxation time. The temperature dependence of these parameters reveals a coupling between adjacent planes of a double plane. The existence of the inter-plane coupling has independently been confirmed by performing N Q R SpinEcho Double Resonance (SEDOR) experiments. The appearance of a spin gap seems to be the consequence of inter-plane coupling.
منابع مشابه
NMR/NQR Spectroscopy
The NMR/NQR group has continued its general research plan of studying current problems of condensed matter physics by employing NMR (nuclear magnetic resonance) and NQR (nuclear quadrupole resonance) methods. These spectroscopies allow one to investigate electronic properties in solids at a microscopic level and thus provide an essential contribution for a better understanding of the materials ...
متن کاملSpin Gap, Electronic Crossover, and Charge Density Waves in Y-Ba-Cu-O Superconductors*
This paper discusses recent NQR/NMR studies performed on Y-Ba-Cu-0 superconductors at the University of Zürich. The work is concerned with normal state properties which are still controversial, for instance the spin-gap effect, i.e. the opening of a pseudo gap in the electron spin excitation spectrum at a temperature 7*, which lies above Tc. We will report on the detection of "anomalies" which ...
متن کاملProbing the Electronic Structure of Y - B a - C u - O Superconductors by Copper NQR/NMR
The paper discusses some N Q R / N M R studies performed on Y B a C u O superconductors at the University of Zürich. It is shown how the resonance methods can yield information on electronic properties of quite different character. The review deals with: (1) the temperature and pressure dependence of Cu N Q R frequencies in YBa 2 Cu 4 O g (1-2-4); (2) an NQR study of the properties of Ca substi...
متن کاملادغام الگوی شبکهای هولشتاین - کاندو برای توصیف نظریه ابررساناهای دمای بالا
It is a common knowledge that the formation of electron pairs is a necessary ingredient of any theoretical work describing superconductivity. Thus, finding the mechanism of the formation of the electron pairs is of utmost importance. There are some experiments on high transition temperature superconductors which support the electron-phonon (e-ph) interactions as the pairing mechanism (ARPES),...
متن کاملA Study of High Tc Oxide Superconductors by NQR and NMR Measurements
Since the discovery of high transition temperature (Tc) superconductors [1] many experimental and theoretical studies have been carried out but still the theories are controversial. In the high TC superconductors, magnetism is considered to play an important role. NMR measurements are suitable to investigate both the magnetic and superconducting properties at each atomic site microscopically. I...
متن کامل