https://doi.org/10.1007/s100510070205
Extension of ferromagnetism and metallicity to electron-rich manganites by Ru-doping: Generation of new CMR oxides Sm0.2Ca0.8Mn1-xRuxO3
1
Laboratoire CRISMAT (UMR 6508 associée au CNRS) , ISMRA, 6 boulevard du Maréchal
Juin, 14050 Caen Cedex, France
2
Institute of Physics of ASCR, Cukrovarnicka 10, 16253 Praha 6, Czech Republic
Corresponding author: a christine.martin@ismra.fr
Received:
2
March
2000
Published online: 15 August 2000
The doping of Mn site with ruthenium, in the n-type manganite Sm0.2Ca0.8MnO3, has been studied using magnetic and transport measurements. We show that Ru induces a ferromagnetic metallic state at low temperature in this Mn4+ rich compound, a metal to metal transition replacing the metal to insulator one in the pristine phase. A spectacular increase of TC up to 240 K is achieved, together with CMR effect. Based on thermoelectric power measurements, we propose that Ru(V) could be at the origin of these exceptional properties, due to ferromagnetic superexchange interactions between Ru(V) and Mn(III), forming in a first step ferromagnetic metallic clusters in the C-type antiferromagnetic insulating matrix.
PACS: 71.30.+h – Metal-insulator transitions and other electronic transitions / 75.50.-y – Studies of specific magnetic materials / 75.30.Et – Exchange and superexchange interactions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
