Abstract
The effect of A-site cationic radius <rA> on structural, electronic and magnetic properties of the perovskite manganites Ln0.67K0.33MnO3 (Ln = La, Pr & Nd) have been investigated. The X-ray diffraction studies show a structural transformation from rhombohedral to orthorhombic with decreasing <rA>. The ferro to paramagnetic transition decreases from 280 to 110 K and the temperature dependent resistivity shows a metal to insulating transition at room temperature for La0.67K0.33MnO3 while insulating behavior was observed in the case of Pr and Nd substituted samples. Further, La0.67K0.33MnO3 sample exhibits room temperature magnetoresistance, and may be exploited for device applications. The sign of the thermopower is negative at 300 K and its magnitude increases with decreasing <rA>. The lanthanum based sample shows an upturn in the resistivity data at 30 K and the observed behavior may be attributed to the combined effect of weak localization, electron–electron and electron–phonon scattering. The paramagnetic insulating part of resistivity and thermopower data was analyzed using small polaron hopping mechanism.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
