ABSTRACTThe effects of disorder on the transport and magnetic properties of pulsed laser deposited La0.7Ca0.3MnO3 thin films were studied. Ion irradiation with 10 MeV I and 6 MeV Si ions was used to produce controlled levels of defects ranging from 0.006 to 0.024 displacements per atom. The peak resistance temperature of the I-irradiated films decreased from 264K for the undamaged film to OK for the 0.016 dpa film. The magnetic ordering temperature decreased from 270K (undamaged) to 130K (0.011 dpa), and remained nearly constant at 130K for higher damage levels. This demonstrates a decoupling of the magnetic and metal-insulator transitions. A characteristic relationship between the peak resistance temperature and activation energy of resistance with the form Tp = 285(1-Δρ/115)0.13, was observed for all films. This characteristic relationship indicates that the range of resistivity and magnetoresistivity values for observed La0.7Ca0.3MnO3 can be explained in terms of disorder-limited polaron hopping.
Accelerating Monte Carlo Bayesian Prediction via Approximating Predictive Uncertainty Over the Simplex
