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

• Published in: Bulletin of materials science 2016-08, Vol.39 (4), p.1109-1117
• Main Authors: JOSHI, ZALAK, PANDYA, D D, DHRUV, DAVIT, GADANI, KEVAL, BORICHA, HETAL, KANSARA, SANJAY, MARKNA, J H, SOLANKI, P S, SHAH, N A
• Format: Article
• Language: English
• Subjects: Bandwidths; Chemistry and Materials Science; Engineering; Manganites; Materials Science; Physical properties; Rare earth elements; Temperature; Thin films; Transport phenomena
• ISSN: 0250-4707; 0973-7669
• DOI: 10.1007/s12034-016-1230-y

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 A 2 ) increased from 3.81 × 10 −5 ( x = 0.05) to 14.9 × 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 ρ – T plots showed resistivity minimum behaviour, which modified with disorder. This behaviour was discussed in detail on the basis of electron–electron interaction having the form: ρ = [ 1 / ( σ 0 + BT 1 / 2 ) ] + ρ n T n . Variation in temperature sensitivity with disorder was also discussed in context of granular morphology and phase segregation scenario.