[en] The topics covered in solid state physics symposium include phase transitions, novel materials, experimental techniques and instrumentation, liquids, glasses and amorphous systems, relaxation studies, surface science, phonons, electronic structure, superconductivity, magnetism, transport properties and semiconductor physics. The papers relevant to INIS are indexed separately

[en] Motivated by recent work on nano tubes which indicate one dimensional quantum effects and well known studies of two dimensional electron gas, we consider a recent description of Fermions in terms of what may be called a quantum mechanical Kerr-Newman metric. We deduce the remarkable fact that this also leads to such an anionic fractionally charged quasi-electron picture but independent of other considerations. An interesting consequence for hadronic interactions is deduced. (author)

[en] Gemini surfactants consist of two hydrophobic chains and two hydrophilic head groups covalently connected by a hydrophobic or hydrophilic spacer. This paper reports the small-angle neutron scattering (SANS) measurements from newly synthesized bis-cationic C₁₆H₃₃N⁺(CH₃)₂-CH₂-(CH₂-O-CH₂)_p- CH₂-N⁺(CH₃)₂C₁₆H₃₃,2Br^- gemini surfactants composed of hydrophilic polyethylene oxide spacer, referred to as 16-CH₂-p-CH₂-16,2Br^-, for spacer lengths p = 1-3. The micellar structures of these surfactant are compared with the earlier studied C₁₆,H₃₃N⁺(CH₃)₂-CH₂)_m-CH₂-N⁺ (CH₃)₂C₁₆H₃₃,2Br^- gemini surfactants composed of hydrophobic poly methylene spacer, referred to as 16-m-16,2Br^-. It is found that 16-CH₂-p-CH₂-16,2Br^- micelles are ellipsoidal for all the values of p 1-3. The micelles are however large in comparison to those of 16-m-16,2Br^-for similar spacer lengths. This is connected with the fact that in 16-CH₂-p-CH₂-16,2Br^- micelles the spacer is more hydrated as compared to that in the 16m-16,2Br^-. An increase in the hydration of the spacer increases the screening of the Coulombic repulsion between the charged head groups and the screening effect increases with an increase in the length of the hydrophilic spacer. (author)

[en] The change in the work function (Δφ) of Si(111) substrate on adsorption of Sm at various coverages (θ) has been determined using Low Energy Electron Diffraction (LEED) optics and retarding potential technique. The data was collected using two different methods. The plot of Δφ verses θ from both the methods shows that the work function of Si(111) decreases rapidly with increasing coverage touches minima and then increases slightly. Thereafter further increase in coverage, does not affect the work function and it remains constant. These observations are explained on the basis of difference in the electronegativity of the semiconductor substrate and the adsorbate. (author)

[en] The structural properties of e-beam deposited (26Fe/89Ni)₁₀ and (32Ti/28Ni)₁₀ multilayer nanostructures of float glass have been investigated using x-ray reflectivity (XRR) and x-ray diffraction (XRD). Measured XRR data of both Ti/Ni and G=Fe/Ni multilayer show Bragg peaks up to the fourth order. XRR analysis is carried out using the optical model. In case of Fe/Ni, roughness is found to increase cumulatively with the number of layers. In case of Ti/Ni multilayer, different interfacial widths are found for Ti-on-Ni and Ni-on-Ti interfaces. XRD results show that Fe and Ni layers are polycrystalline in case of Fe/Ni multilayer and Ti/Ni layers are amorphous in case of Ti/Ni multilayer. (author)

[en] All-electron local-density full-potential augmented plane wave (FP-LAPW) method has been used to calculate the electronic structure and phase stability of Ni-Mo intermetallics. There is a competition between several fcc-based ordered intermetallic phases in Ni-Mo alloys containing 8-33 at % Mo, whose total ground state energies and other derived cohesive properties have been evaluated with fraction of a mRy accuracy. These fully relaxed calculations delineate the minute differences in the relative stability of the fcc-based DO₂₂ and the hcp-based DO_a structure of Ni₃Mo phase. Furthermore, using the SCW model, we have estimated the free energies of these phases as a function of temperature, composition and order parameter, which in turn helped predicting the ordering behaviour and the sequence of transformation in these alloys. (author)

[en] The temperature dependence of electrical resistivity of YBa₂Cu₃ O_7-x/Ag composite thick films is studied. The films are prepared by reaction diffusion between a high melting point Y₂BaCuO substrate and low melting point Ba₃Cu₅O₈ coating layer. Addition of Ag₂O to the coating layer aided diffusion and formed a laminated layer composed of Ag and the superconducting layer on top of the substrate. The granularity parameters such as weak link resistivity ρ_wl and percolative conduction factor α arising due to current frustration caused by misalignment of grains and sample defects like voids and cracks are estimated from residual resistivity, ρ_o and slope of the curves dρ/dT. Ag is shown to significantly modify microstructure in YBCO/Ag composites in terms of drastic reduction of weak link resistivity and provide better alignment of anisotropic YBCO grains. (author)

[en] NMR investigations of ⁴⁵Sc and ²⁷Al are carried out on the Heusler alloy ScNi₂Al in the temperature range 300-7.5 K, to study the nature of the Ni-3d electrons. The NMR spectra do not show any static quadrupole effects and both sites have temperature independent Knight shifts. Longitudinal relaxation time measurements show that T₁T is a constant for both the nuclei, indicating that magnetic correlations between the Ni-3d electrons are absent in this material. (author)

[en] It has been reported that the addition of equal amounts of CaO and CuO into nonsuperconducting La₃Ba₃Cu₆O_z (La-336) and LaBaCu₂O_z (La-112) resulted in to the occurrence of superconductivity with La₃Ca₁Ba₃ Cu₇O_z(La-3137) and LaCaBaCu₃O_z (La-1113) systems respectively. We report for the first time studies on the superconducting properties of La₂Ca Ba₂Cu₅O_z (La-2125) phase obtained from non superconducting La₂Ba₂ Cu₄O_z (La-224) by addition of CaCuO₂ layers. Also, we present the results of the studies on samples having large La³⁺ ion replaced by smaller rare earth ions like Er³⁺, Gd³⁺ or Yb³⁺ having the stoichiometric compositions (La_2-xR_x)Ba₂(Ca_yCu_4+y)O_z (LRBCaC); (R=Er, Gd or Yb) 0.0 ≤ x ≤ 0.5; y=2x. These results will be discussed in the context of role played by Ca-Cu addition on the revival of superconductivity in non superconducting La-224 and the dependence of T_c on hole concentration. (author)

[en] The hole states located on different oxygen sites have been investigated for Eu_0.9-xPr_xCa_0.1BaSrCu₃O_7-δ as a function of Pr³⁺ substitution, by the high resolution oxygen K-edge and copper L-edge x-ray absorption spectra. The results reveal that the hole states are depleted systematically by the Pr substitution and in turn lead to a reduction in the T_c. Depletion of hole states by the Pr substitution give evidence in support of the hole-depletion model proposed by Liechtenstein and Mazin (LM). (author)