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G. B. Teitel'baum

Publications and source records attributed to G. B. Teitel'baum.

7 recordsLinked to original sources
arXiv2012

ESR of coupled spin-1/2 chains: unveiling zig-zag-type interchain correlations

By means of electron spin resonance investigations we revealed the crucial role of the interchain coupling in the spin dynamics of the spin-1/2 Heisenberg antiferromagnetic (AF) chain material copper-pyrazine-dinitrate, Cu(C$_4$H$_4$N$_2$)(NO$_3$)$_2$. We found that the dominating interchain interaction is of a zig-zag type. This interaction gives rise to geometrical frustration effects and strongly influences the character of AF ordering. Combining our experimental findings with the results of a quasiclassical approach we argue that at low temperatures the system orders in an incommensurate spiral state.

cond-mat.str-el↗
arXiv2004

Pseudogap behavior of nuclear spin relaxation in high Tc superconductors in terms of phase separation

We analyze anew experiments on the NMR in cuprates and find an important information on their phase separation and its stripe character hidden in the dependence of $1/^{63}T_{1}$ on degree of doping. In a broad class of materials $1/^{63}T_{1}$ is the sum of two terms: the temperature independent one attributed to ``incommensurate'' stripes that occur at external doping, and an ``universal'' temperature dependent term ascribed to moving metallic and AF sub-phases. We argue that the frustrated first order phase transition in a broad temperature interval bears a dynamical character.

cond-mat.str-el↗
arXiv2004

Nuclear spin relaxation and incommensurate magnetism in doped cuprates

Existing data on Cu-nuclear spin relaxation reveal two independent relaxation processes: the one that is temperature independent we link to incommensurate peaks seen by neutrons, while the ''universal'' temperature dependent contribution coincides with 1/{63}^T_{1}(T) for two-chain YBCO 124. We argue that this new result substitutes for a ''pseudogap'' regime in a broad class of high-T_c cuprates and stems from the 1st order phase transition that starts well above the superconductivity T_c but becomes frustrated because of broken electroneutrality in the CuO_2 plane.

cond-mat.supr-con↗
arXiv2003

Interplay between the magnetic fluctuations and superconductivity in the lanthanum cuprates

We report the analysis of the magnetic fluctuations in the superconducing La_{2-x}Sr_xCuO_4 and the related lanthanum cuprates having the different symmetry of the low temperature structure. The NMR and ESR investigations revealed the dynamical coexistence of the superconductivity and the antiferromagnetic correlations in the large part of superconductivity region of the phase diagram. We show that for all compounds, independent on their low temperature symmetry and on their superconducting properties, the enhancement of the spin stiffness near 1/8 doping takes place.

cond-mat.supr-con↗
arXiv2000

Spin dynamics and ordering of a cuprate stripe-antiferromagnet

In La1.48Nd0.4Sr0.12CuO4 the 139La and 63Cu NQR relaxation rates and signal wipe-out upon lowering temperature are shown to be due to purely magnetic fluctuations. They follow the same renormalized classical behavior as seen in neutron data, when the electronic spins order in stripes, with a small spread in spin stiffness (15% spread in activation energy). The La signal, which reappears at low temperatures, is magnetically broadened and experiences additional wipe-out due to slowing down of the Nd fluctuations.

cond-mat.str-el↗
arXiv1999

The Cu NQR Study of the Stripe Phase Local Structure in the Lanthanum Cuprates

Using Cu NQR in Eu-doped La_{2- x}Sr_xCuO_4 we show the evidence of the pinned stripe phase for moderate doping at 1.3K. The pinned fraction increases by one order of magnitude near hole doping x=1/8. The NQR lineshape reveals three inequivalent Cu positions: i) sites in the charged stripe; ii) nonmagnetic sites outside the stripes; iii) sites with a magnetic moment of 0.29 Bohr magnethon in the AF correlated regions. A dramatic change of the NQR signal for x > 0.18 correlating with the onset of bulk superconductivity corresponds to the depinning of the stripe phase. .

cond-mat.str-el↗