  By laser ablation we prepared thin films of the colossal magnetoresistive
compound La_(1-x)Ca_xMnO_3 with doping levels 0.1<x<0.9 on MgO substrates.
X-ray diffraction revealed epitaxial growth and a systematic decrease of the
lattice constants with doping. The variation of the transport and magnetic
properties in this doping series was investigated by SQUID magnetization and
electrical transport measurements. For the nonmetallic samples resistances up
to 10^13 Ohm have been measured with an electrometer setup. While the transport
data indicate polaronic transport for the metallic samples above the Curie
temperature the low doped ferromagnetic insulating samples show a variable
range hopping like transport at low temperature.

Strongly Correlated Electrons;Materials Science