Colossal Magnetoresistance in the Mn2+ Oxypnictides NdMnAsO1-xFx
  Colossal magnetoresistance (CMR) is a rare phenomenon in which the electronic resistivity of a material can be decreased by orders of magnitude upon application of a magnetic field. Such an effect could be the basis of the next generation of magnetic memory devices. Here we report CMR in the antiferromagnetic oxypnictide NdMnAsO1-xFx as a result of competition between an antiferromagnetic insulating phase with strong electron correlations and a paramagnetic semiconductor upon application of a magnetic field. The discovery of CMR in antiferromagnetic Mn2+ oxypnictide materials could open up an array of materials for further investigation and optimisation for technological applications. 
E. J. Wildman, J. M. S. Skakle, N. Emery and A. C. Mclaughlin
cond-mat.str-el cond-mat.mtrl-sci cond-mat.supr-con