Structural and magneto-transport properties of Li-substituted La0.65Ca0.35-xLixMnO3 (0 ≤ x ≤ 0.15) CMR manganites

• Published in: Journal of alloys and compounds 2020-01, Vol.814, p.1, Article 152279
• Main Authors: Verma, Mukesh Kumar, Sharma, Narayan Dutt, Sharma, Suman, Choudhary, Nisha, Singh, Devinder
• Format: Article
• Language: English
• Subjects: Curie temperature; Exchanging; Ferromagnetism; High temperature; Low temperature; Magnetic properties; Magnetoresistance; Magnetoresistivity; Manganites; Metal/semiconductor transitions; Sol-gel processes; Transition temperature; Transport properties
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.152279

With an aspect to understand the influence of cation mismatch on magneto-transport properties of colossal magnetoresistive (CMR) materials, a systematic study of La0.65Ca0.35-xLixMnO3 (0 ≤ x ≤ 0.15) manganites has been undertaken. The materials were synthesized by sol-gel Pechini process and their structures were confirmed by the analysis of XRD data using Rietveld refinement technique. A paramagnetic to ferromagnetic transition and a semiconductor to metallic one have been observed at low temperature. Both Curie temperature (Tc) and metal-semiconductor transition temperature (TMS) in the vicinity of Tc first increases with Li doping and then show a decreasing trend, which is justified on the basis of a competition between double-exchange and super-exchange mechanisms. It has been concluded that the electrical resistivity data in high-temperature paramagnetic-semiconducting region (T > TMS) may be described by the small polaron hopping model. Also, a large magnetoresistance (MR%) has been observed in the vicinity of metal-semiconductor transition temperature TMS, which is comparable to the MR% in the low-temperature region. •La0.65Ca0.35-xLixMnO3 CMR materials were synthesized by sol-gel Pechini process.•Both Tc and TMS show similar trend.•The conduction mechanism is dominated by SPH model.•A large MR% has been observed in the vicinity of TMS.