• P S SOLANKI

Articles written in Bulletin of Materials Science

• Investigations on structural disorder-induced modifications in the transport behaviour of rare-earth manganites

The results of the studies on structural disorder-induced modifications in the transport behaviour of La$_{0.5}$Pr$_{0.2}$Ca$_{0.3−x}$Ba$_x$MnO$_3$ (LPCBMO) ($0.05 ≤ x ≤ 0.30$) manganites were reported. Structural studies using X-ray diffraction (XRD) measurements confirmed the single phasic nature of all the samples without any detectable impurities. The A-site size disorder ($σ_2$ A) increased from $3.81 \times 10^{−5} (x = 0.05)$ to $14.9 \times 10−5 (x = 0.30)$. With the increase in structural disorder in LPCBMO system, the transport improved for the range: $0.15 ≤ x ≤ 0.30$, which can be ascribed to the enhancement in one electron bandwidth which dominates over the structural disorder effect, while for lower values of $x$, strong competition existed between size disorder and one electron bandwidth. Below 50 K, all $\rho–T$ plots showed resistivity minimum behaviour, which modified with disorder. This behaviour wasdiscussed in detail on the basis of electron–electron interaction having the form: $\rho = [1/(\rho_0 + BT^{1/2})] + \rho_nT_n$. Variation in temperature sensitivity with disorder was also discussed in context of granular morphology and phasesegregation scenario.

• Charge conduction mechanisms and MR behaviour of sol–gel-grown nanostructured La$_{0.6}$Nd$_{0.1}$Sr$_{0.3}$MnO$_3$ manganites

In this communication, structure and charge, conduction mechanisms have been understood for sol–gel grown nanostructured La$_{0.6}$Nd$_{0.1}$Sr$_{0.3}$MnO$_3$ (LNSMO) manganites prepared at different process temperatures under air and oxygen environments. Obtained X-ray diffraction patterns of all the samples were analysed using Rietveld refinements and obtained structural lattice parameters have been discussed in correlation with resistivity behaviour of the samples. Observed low temperature resistivity upturn behaviour has been examined in the context of electron–electron scattering mechanism. Metallic and insulating/semiconducting behaviours of all the nanostructured LNSMO manganites have been understood by using various models and mechanisms. Magnetoresistance isotherms have also been theoretically fitted and separate grain and grain boundary contributions have been studied for LNSMO manganite samples. Allobtained fitting parameters have been discussed in the context of role of applied magnetic field, process temperature and annealing environment.

• Thermal effects on resistive switching in manganite–silicon thin film device

In this article, we report the results of the fabrication and studies of Y$_{0.95}$Ca$_{0.05}$MnO$_3$/Si device (referred hereafter as YCMO/Si) by pulsed laser deposition (PLD) and its temperature-dependent resistive switching (RS) behaviours measured across the YCMO/Si interface. These temperature (100–300 K)-dependent hysteretic current–voltage ($I–V$) characteristics have been understood on the basis of various possible charge conduction mechanisms involving the thermal effects on the charge carriers during four different cycles of the RS behaviours. Variations in the values of barrierheight and the ratio of free to trapped charge carrier densities with temperature have been discussed for reverse bias mode of this YCMO/Si device. Temperature-dependent temperature coefficient of resistance (TCR) under different applied forward voltages shows an interesting variations in TCR with applied forward voltage, which proves this device as a potential candidate for practical applications.

• # Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020

Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019

Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.