arXiv subjects

B. Birajdar

Publications and source records attributed to B. Birajdar.

3 recordsLinked to original sources

arXiv2025

Disorder Induced Superconductivity in TiSe_1.2S_0.8

Disorder can be utilized as an effective parameter to probe the interplay between two long range orders such as superconductivity and charge density wave. In the present work, we report on the experimental evidence for filamentary superconductivity in polycrystalline TiSe1.2S0.8 with superconducting transition Tc ~ 7K. This is validated from magnetization and magneto-transport measurements. Strain induced dislocations, substitutional defects, and randomly distributed Ti ions (with local moments) are considered as possible sources of disorder. A detailed analysis of the temperature dependent resistivity evaluates the degree of disorder and the consequent localization effects. The findings are in striking contrast to the fact that superconductivity has not been reported in single crystals of TiSe2-xSx system. It is established that disorder serves as a stabilizing factor for the superconducting phase due to in-commensuration of the charge density wave.

cond-mat.supr-con↗

arXiv2023

Electromagnetic properties of copper doped lead apatite Pb9Cu(PO4)6O

We report on the structural, electrical and magnetic measurements in as-grown polycrystalline samples of Pb10-xCux(PO4)6O. This compound has been recently reported to be a room temperature superconductor. Our as-grown specimen has excellent XRD matching with the original submission of Lee et al. This sample has 1.5% of Cu2S as an impurity phase. A resistive transition around 380 K, possibly corresponding to structural transitions of Cu2S, is observed. No evidence of superconducting to normal state transitions in I-V characteristics at room temperature is obtained. Magnetization measurements show linear diamagnetic behavior that cannot be associated to the superconducting state. Hall measurements provide evidence of hole doping through Cu substitution. In summary, we find no evidence for room temperature ambient pressure superconductivity in Cu doped lead apatite Pb9Cu(PO4)6O.

cond-mat.mtrl-sci↗

arXiv2016

Evolution of Microstructure and Relaxor Ferroelectric Properties in (La_zBa_(1-z)(Ti0.80Sn0.20)O3

We report a study on a series of lanthanum doped barium stannate-titanate (LBTS) ceramics towards correlating their microstructure with ferroelectric properties. The samples were prepared by solid state reaction technique and the XRD analysis indicated predominantly single phase microstructure. Scanning Electron Microscopy revealed that while a low La doping of 1 atomic % yielded inhibited grain growth in 1LBTS, higher amounts of La doping yield larger leafy grains. This peculiar grain growth and microstructure evolution could be attributed to the combination of the following two competing factors: (i) suppression of O vacancies due to La doping leading to grain growth inhibition and (ii) enhancement of mechanism leading to nucleation and growth of 2-D (leafy) grains for La doping higher than 2 atomic % due to eutectic phenomena. Dielectric permittivity measurements indicate that addition of La enhances diffused phase transition in BTS, but its frequency dependence is observed only at 2 atomic % La doping. This signature relaxor behaviour and the increase in the intensity of a particular Raman peak with La doping, as well as non-saturated PE hysteresis loops confirm the presence of polar nano-regions for 2 and 3 atomic % La doped BTS. However significant enhancement in dielectric permittivity could not be achieved due to reduced grain size.

cond-mat.mtrl-sci↗