Magnetoresistance of Lanthanum-based Perovskite Manganites

The magnetoresistive behavior of perovskite manganites that have been electrochemically deposited on iron and silver substrates, as well as bulk samples prepared by standard methods, will be discussed. Effects of post deposition treatment to alter grain boundaries, grain sizes, oxygen content and other parameters will also be discussed. The samples were characterized using scanning electron microscopy (SEM), energy dispersive x-ray (EDX) analysis and x-ray diffraction (XRD) measurements. The temperature dependence of the electrical resistance of the samples were measured by a standard four-probe method at temperatures up to 380 K and in magnetic fields up to 17 T* generated by a superconducting magnet. A zero field peak in the resistance above 300 K was observed in the thin films. Magnetization of the samples were measured using a superconducting quantum interference device (SQUID) magnetometer. *Performed at the National High Magnetic Field Lab (NHMFL) FSU, Tallahassee, FL