A comparative study of magnetotransport and magnetization in epitaxial La0.6Nd0.2Ca0.2MnO3 unirradiated and heavy ion irradiated thin films

Epitaxial thin film of La0.6Nd0.2Ca0.2MnO3 has been irradiated with 80 MeV oxygen ions at a dose of 1013 ions/cm2. The films were deposited at 800 °C on LaAlO3 substrate using pulsed laser deposition technique. The structural, magnetization and magnetotransport properties of both irradiated and unirradiated films have been studied. The unirradiated film displays a very large magnetoresistance around 95% in the low temperature regime possibly due to induced grain boundaries and lattice strain effects. On the other hand, the irradiated film exhibits a large nearly temperature independent magnetoresistance around 98% in the low temperature regime, due to the radiation induced clustering of defects. The magnetoresistance data has also been analyzed in terms of modified Mottʹs hopping model and the results are presented. An unusual zero field cooled and field cooled magnetization at 0.005 T has been observed for both irradiated and unirradiated films. The observed results are explained in terms of point/cluster of defects induced disorder and its influence on the magnetotransport properties.