Study of Physical Properties of Charge Ordered CMR Manganites

Doped rare-earth perovskite manganites shows a strong interplay between charge, spin and lattice degrees of freedom leading to a rich phase diagram with varieties of electronic, magnetic and structural phases, competing and cooperating with each other. These materials exhibit colossal magnetoresistive (CMR) property near the Curie temperature. Due to these properties manganites find their possible applications in advanced electronic devices like magnetic read heads, magnetic data storage devices, spintronic devices, magnetic sensors, magnetic refrigeration etc. which has boosted the importance of the study of these compounds. We propose here a double exchange model Hamiltonian consisting of charge ordering as an extra-mechanism in presence of electron-phonon interaction to explain the observed CMR phenomenon. The CMR phenomenon has been tried to be explained through the study of temperature dependent magnetization, electron occupation number, magnetic susceptibility, velocity of sound, ultrasonic attenuation and Raman spectra. In all these studies we observe clear signature of CMR behavior.