• KEVAL GADANI

      Articles written in Bulletin of Materials Science

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

      ZALAK JOSHI D D PANDYA DAVIT DHRUV KEVAL GADANI HETAL BORICHA SANJAY KANSARA J H MARKNA P S SOLANKI N A SHAH

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      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.

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

      AMIRAS DONGA K N RATHOD KEVAL GADANI DAVIT DHRUV V G SHRIMALI A D JOSHI K ASOKAN P S SOLANKI N A SHAH

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      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.

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