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An open access copy of this article is available and complies with the copyright holder/publisher conditions.
An open access copy of this article is available and complies with the copyright holder/publisher conditions.
We report here our Raman studies on Fe3–xZnxO4(x = 0,0.015,0.03) across the Verwey transition in the temperature range 20–300 K. The changes in Raman spectra as a function of doping show that the changes are gradual for samples with higher Zn doping. Allen's formula has been used to estimate the strength of electron-phonon interaction from the observed lineshape parameters. These estimates show that there is strong electron-phonon coupling in this system and is highest for the T mode in comparison to A1g and T modes.
We have performed sound velocity measurements in (V$_{1-x}$Cr$_x$)$_2$O$_3$ in the vicinity of the critical point of the first order Mott transition line. The pressure sweeps at constant temperature reveal a large dip in the $c_{33}$ compression modulus, this dip sharpens as the critical point is approached. We do not observe signs of criticality on the shear modulus $c_{44}$ which is consistent with a transition governed by a scalar order parameter, in accordance with the DMFT description of the transition. However, the amplitude of the effect is an order of magnitude smaller than the one obtained from DMFT calculations for a single band Hubbard model. We analyze our results using a simple model with the electronic response function obtained from the scaling relations for the conductivity.
An open access copy of this article is available and complies with the copyright holder/publisher conditions.
DsbC and DsbG are periplasmic disulfide-bond isomerases, enzymes that facilitate the folding of secreted proteins with multiple disulfide bonds by catalyzing disulfide-bond rearrangement. Both enzymes also have in vitro chaperone activity. The crystal structures of these molecules are similar and both are V-shaped homodimeric modular structures. Each dimeric molecule contains two separate C-terminal thioredoxin-fold domains, joined by hinged helical ‘stalks’ to a single N-terminal dimerization domain formed from the N-terminal 67 residues of each monomer. In this work, the crystal structures of the separate DsbC and DsbG dimerization domains have been determined at resolutions of 2.0 and 1.9 A ° , respectively. The two structures are both similar to the corresponding domains in the full-length molecules, showing that the dimerization d...
We present the results for the temperature and field dependence of the magnetic for ceramic materials of the composition La2−xMxNiO4, with M=Sr or Ca and 0≤x≤0.4. The onset of a strong diamagnetism has been observed at temperatures between 8 and 70 K, depending on sample composition, annealing conditions. and thermal cycling procedures. The results are similar to those obtained earlier for monocrystalline samples and are likewise interpreted as due to the onset of superconductivity in a minority phase. A comparison with the results for superconducting La1.8Sr0.2Cu0.9Ni0.1O4 ceramics is also made; this illustrates some unique features of the nickelate systems, such as the high values of the critical fields Hc1 and Hc2. The differences between monocrystalline and ceramic systems are also discussed.
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