We review recent NMR studies of the layered organic superconductors of the (BEDT)2X family. First the normal state properties are discussed. The central issue is the importance of the interplay between antiferromagnetism and superconductivity in these materiais demonstrated by the observation of a pseudogap developing prior to the superconducting transition. An extended analysis of the Knight s...

According to Wilson's theory of critical phenomena, critical exponents are universal functions of d, the dimension of space, and n, the dimension of the symmetry group. SO(5) theory of antiferromagnetism and superconductivity predicts a bicritical point where TN and T~ intersect. By measuring critical exponents close to the bicritical point, and knowing that d = 3, one can experimentally measur...

An ab initio linearized augmented plane-wave method has been employed to calculate the electronic and magnetic structures of both face-centered-cubic and body-centered-cubic Fe12xPdx alloys with x50.25, 0.50, and 0.75, respectively. Decreasing the Pd content in Fe12xPdx alloy from x51, the magnetic ordering of fcc Fe12xPdx changes from paramagnetism to ferromagnetism, ferrimagnetism, and finall...

Motivated by recent experiments with Bechgaard salts, we investigate the competition between antiferromagnetism and triplet superconductivity in quasi-one-dimensional electron systems. We unify the two orders in an SO(4) symmetric framework, demonstrating the existence of such symmetry in one-dimensional Luttinger liquids. SO(4) symmetry strongly constrains the phase diagram, leading to coexist...

The one-particle spectral function of a state formed by superconducting (SC) clusters is studied via Monte Carlo techniques. The clusters have similar SC amplitudes but randomly distributed phases. This state is stabilized by competition with the antiferromagnetism expected to be present in the cuprates and after quenched disorder is introduced. A Fermi surface composed of disconnected segments...

Local antiferromagnetism coexists with superconductivity in the cuprates. Charge segregation provides a way to reconcile these properties. Direct evidence for modulated spin and charge densities has been found in neutron and X-ray scattering studies of Nd-doped La2−xSrxCuO4. Here we discuss the nature of the modulation, and present some new results for a Zn-doped sample. Some of the open questi...