Kar, Manoranjan2016-06-272023-10-262016-06-272023-10-262004ROLL NO.994403http://172.17.1.107:4000/handle/123456789/720Supervisor: S. RaviMaterials based on manganese oxides are generally known as manganites. The manganites RMnO3 (R= Trivalent rare earth elements) and AMnO3 (A= Divalent alkaline earth elements) are known to be insulating with antiferromagnetic (AFM) ordering. Even though the mixed valence manganites, R1-xAxMnO3 (x <= 0.50) are known to exhibit ferromagnetic (FM) to paramagnetic and metal-insulator transitions as early as 1950, the interest in this type of compounds was renewed only after the discovery of large negative magneto-resistivity in the vicinity of the transition temperature (Tc). The Phenomenon of large...enPHYSICSThesis