Nature Materials 2, 247–252 (2003).

It has been drawn to the journal's attention that there is considerable overlap between an earlier publication by these authors1 and the material and conclusions presented in this paper. The failure to declare the previous publication is in breach of Nature Materials strict publication policy (http://www.nature.com/nmat/authors/auguide.html).

In addition, there is an error in Table 1 of the Nature Materials paper: CMRmax should be 105 for 0.33 MgO content.