Ru doping of the A-type antiferromagnet Pr0.5Sr0.5MnO3: Conversion to a metallic ferromagnet

The doping of Mn sites of the A-type antiferromagnet Pr0.5Sr0.5MnO3 with ru thenium shows that ferromagnetism and metallicity are induced similarly to the doping of the CE-type phases Ln(0.5)Ca(0.5)MnO(3). This effect, similar to the Cr doping, differs from the latter by the fact that T-C = T-IM incr eases significantly with the Ru level. The different behaviors of Ru and Cr doped Pr0.5Sr0.5MnO3 samples are interpreted on the basis of two factors, ferromagnetic superexchange introduced by the magnetic dopants, and valency effect which contributes to increase the Mn3+ content for Ru(IV) and Ru(V) and does the opposite for Cr(III). (C) 2001 American Institute of Physics.