Solid State Science and Technology, Vol. 18, No 2 (2010) 9-14
INFLUENCE OF La3+ WITH Pr3+ TO STRUCTURE, MICROSTRUCTURE, AND MAGNETOTRANSPORT PROPERTIES IN BARIUM MANGANITE PEROVSKITE
J.K. Wong, K.P. Lim, S.A. Halim, S.K. Chen and S.W. Ng
Department of Physics, Faculty of Science, Universiti Putra Malaysia.
43300 UPM Serdang, Selangor, Malaysia
Polycrystalline perovskite manganite of (La,Pr)0.67Ba0.33MnO3 bulk ceramic samples were synthesized by conventional solid-state route. The structure, microstructure, electrical and magnetic properties were studied. Substitution of La3+ with Pr3+ promote coarsening of microstructure formation and influencing the connectivity of grains which resulting an increase in resistance. This substitution promotes magnetic dilution and consequently leading to the suppression of magnetic behaviour. The metal-insulator transition temperature, TP drops drastically from 264K (LBMO) to 127K (PBMO). PBMO displayed higher %MR in 10kG applied external magnetic field at room temperature which is -8.8% as compared to LBMO (-5.2%) because of magnetic dilution and reduced the magnetic saturation. Meanwhile, reduction in bond angle and bond length of Mn3+-O2--Mn4+ due to the distortion in MnO6 might enhance DE and JT mechanism. In this work, the %MR at room temperature enhanced by replacing La3+ with Pr3+ but weaken the LFMR effect.
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