Strong magnetoresistance in PrBa2Cu3Ox epitaxial films

We report strong negative magnetoresistance in epitaxial PrBa2Cu3Ox, films prepared by laser ablation on SrTiO3 substrates. Magnetoresistance appears at temperatures below similar to 50 K. At 10 K its value reaches 90% in a m agnetic field of 0.5 T. The magnetoresistance is strongly suppressed near 2 0 K where the Pr ions undergo antiferromagnetic ordering. Post annealing in flowing oxygen reduces the magnetoresistance by a factor of about three an d slightly increases the antiferromagnetic ordering temperature.