Phonon response of some heavy Fermion systems in dynamic limit

The phonon excitation spectrum of some Heavy Fermion (HF) systems in the presence of electron–phonon interaction is studied in the dynamic limit ([Formula: see text]). The renormalized excitation phonon frequencies ([Formula: see text]) are evaluated through Periodic Anderson Model (PAM) in the presence of electron–phonon interaction using Zubarev-type double time temperature-dependent Green function. The calculated renormalized phonon energy is analyzed through the plots of ([Formula: see text]) against temperature for different system parameters like effective coupling strength ‘[Formula: see text]’ and the position of [Formula: see text]-level ‘[Formula: see text]’. The observed behavior is analyzed and found to agree with the general features of HF systems found in experiments. Further, it is observed that in finite but small [Formula: see text]-values the propagating phonons harden and change to localized peaks. </jats:p

Anisotropy of Sommerfeld coefficient and penetration depth in superconducting 2H-NbS

We proposed anisotropic properties of Sommerfeld coefficient as well as penetration depth for superconducting 2H-NbS2 by using modified phenomenological GL-theory for multi band superconducting system. Calculated results are very close with the corresponding experimental findings reported earlier. Similarly, anisotropy of penetration depths obtained successfully following the same model of GL-theory. The analysis reveals that present proposed model can successfully be used for explaining anisotropy of transitional metal dichalcogenide compounds (TMDs)

GROWTH OF FOURTH GENERATION ELONGATED TIO2 NANOTUBES IN MIXED ELECTROLYTES

Objective The effects of oxalic acid and phosphoric acid mixture in the formation of enlarged titanium oxide nanotubes was investigated in the current study. Methods The anodizaion was carried out in an aqueous electrolyte containing oxalic acid, phosphoric acid, hydrogen peroxide in ethylene glycol in a simple two electrode system at room temperature by using potentiostat set up. ResultsThe coexistence of anatase and rutile phases were noticed to be from higher ratio of anatase peaks to rutile peaks. Diameter of the TNTs increased with elevated applied voltage. At low voltage, random cracks with no noticeable structure was seen on the Ti substrate. But on increasing value of the applied potential, determinable tubular structure of TNTs emerges in the crack. Maximum number of E.Coli bacteria were noticed on the agar medium without TiO2 nanoparticles than observed on the agar medium with TiO2 nanoparticles. Conclusion The presence of H3PO4 in the electrolyte, enhanced the growth of nanotube diameter and length. The ionic current increased with increase in H3PO4 concentration that lead to formation of oxide layer and increase in oxide forming efficiency. Having better mechanical properties, adhesion strength, surface roughness, hydrophilic properties, the anodized titania nanotube surfaces are envisaged to have better cell activity, biocompatibility with antimicrobial property and also longevity. It can be applicable as the better implant surface in human body environment. Keywords: TiO2 nanotubes; anodization; oxalic acid; fluorine free; antibacterial

Modification of structural and dielectric properties of polycrystalline Gd-doped BFO–PZO

(1−y)(BiFe1−xGdxO3)–y(PbZrO3) composites (y=0.5), having four different Gd concentrations (x=0.05, 0.1, 0.15, and 0.2), were synthesized and their structural, dielectric, and ferroelectric properties have been studied using different characterization techniques. In addition, to investigate the effect of ion implantation on the microstructure and dielectric properties, these composites were exposed to 2MeV He+-ions. Modifications of the structure, surface morphology and electrical properties of the samples before and after ion exposure were demonstrated using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) technique, and LCR meter. The compositional analysis was carried out using energy dispersive X-ray spectrometry (EDS). XRD results demonstrated a decrease in the intensity profile of the dominant peak by a factor of 6 showing a degradation of the crystallinity. Willliamson–Hall (WH) plots reveal reduction in the grain size after irradiation along with an increase in strain and dislocation density. A decrease in the dielectric constant and loss has been recorded after ion beam exposure with reduction in ac conductivity value. The contribution of grain and grain boundary effect in conduction mechanism has been addressed using Nyquist plots. All the samples demonstrate a lossy ferroelectric loop which shows a clear modification upon irradiation. The role of structural defects modifying the physical properties of the composite materials is discussed in this work