Related papers: Spin Defects in Spin-Peierls Systems

Using 63Cu NMR, we establish that the enhancement of spin order by a magnetic field H in YBa2Cu3O6.45 arises from a competition with superconductivity because the effect occurs for H perpendicular, but not parallel, to the CuO2 planes, and…

A phenomenological model of the Landau type forms the basis for a study of elastic distortions near the spin-Peierls transition $T_c$ in $CuGeO_3$. The atomic displacements proposed by Hirota {\it et al.} [Phys. Rev. Lett. {\bf 73}, 736…

The fraction of the paramagnetic phase surviving at the impurity-induced antiferromagnetic order transition of the doped spin-Peierls magnet Cu(1-x)Mg(x)GeO3 (x < 5%) is found to increase with an external magnetic field. This effect is…

The spin dynamics of high temperature superconductors measured by inelastic neutron scattering is reviewed. The spin susceptibility evolves a lot with increasing doping from the undoped insulating state to the overdoped metallic state. In…

The spin$-1/2$ chain with ferromagnetic exchange $J_1 < 0$ between first neighbors and antiferromagnetic $J_2 > 0$ between second neighbors supports two spin-Peierls (SP) instabilities depending on the frustration $\alpha = J_2/\vert…

Recently we have computed the third order corrections to the ground state energy of the arbitrarily polarized diluted gas of spin 1/2 fermions interacting through a spin-independent repulsive two-body potential. Here we extend this result…

I review recent work on magnetic dynamics of the high temperature superconductors using a model that combines two weakly interacting species of low-energy excitations: the antiferromagnetic spin waves which carry spin-1 and no charge, and…

Spin-polarons are obtained using an Ising-like exchange model consisting of double and super-exchange interactions in low dimensional systems. At zero temperature, a new phase separation between small magnetic polarons, one conduction…

The tension between fermion pairing and magnetism affects numerous strongly correlated electron systems, from high-temperature cuprates to twisted bilayer graphene. Exotic forms of fermion pairing and superfluidity are predicted when…

We investigated magnetization, muon spin rotation ($\mu$SR), and $^{119}Sn$ M\"{o}ssbauer spectroscopy on Sn substituted $CuCr_{2-x}Sn_xS_4$ (x=0.03 and 0.08) spinel compounds. The magnetization and $\mu$SR results reveal similar additional…

Dielectric and magnetic properties have been studied for poly-crystalline samples of quasi-one-dimensional frustrated spin-1/2 system Rb$_{2}$(Cu$_{1-x}$M$_{x}$)$_{2}$Mo$_{3}$O$_{12}$(M=Ni and Zn) which does not exhibit a three-dimensional…

At room temperature, the normal oxide spinels NiCr_2O_4 and CuCr_2O_4 are tetragonally distorted and crystallize in the I4_1/amd space group due to cooperative Jahn-Teller ordering driven by the orbital degeneracy of tetrahedral Ni$^{2+}$…

Dy$_{2}$Zr$_{2}$O$_{7}$ a disordered pyrochlore system, exhibits the spin ice freezing under the application of magnetic field. Our studies suggest the stabilization of pyrochlore phase in Dy$_{2-x}$La$_{x}$Zr$_{2}$O$_{7}$ with the…

The spin-Peierls phase transition in CuGeO_3 has been extensively studied utilizing a variety of experimental techniques. Interpretations of the phase transition behavior vary from tricritical to mean field to Ising critical to XY critical.…

In this paper we compute the mean field phase diagram of a doped antiferromagnet, in a magnetic field and with anisotropic exchange. We show that at zero temperature there is a metamagnetic transition from the antiferromagnetic…

We discovered a first-order phase transition between dimerized-antiferromagnetic and uniform-antiferromagnetic phases in impurity-doped spin-Peierls (SP) cuprate Cu{1-x}MgxGeO3. As impurity concentration increases, linear reduction of SP…

Using inelastic magnetic neutron scattering we have discovered a localized spin resonance at 4.5 meV in the ordered phase of the geometrically frustrated cubic antiferromagnet $\rm ZnCr_2O_4$. The resonance develops abruptly from quantum…

We consider the superstructures, which can be formed in spinels containing on B-sites the transition-metal ions with partially filled t2g levels. We show that, when such systems are close to itinerant state (e.g. have an insulator-metal…

Effects of nonmagnetic impurity doping in a spin ladder system with a spin gap are investigated by the exact diagonalization as well as by the variational Monte Carlo calculations. Substantial changes in macroscopic properties such as…

We report the phase diagram of the doping series U_2Pt_xRh_(1-x)C_2, studied through measurements of resistivity, specific heat and magnetic susceptibility. The Neel temperature of U_2RhC_2 of ~ 22 K is suppressed with increasing Pt…