J. Phys. IV France 07 (1997) C1-621-C1-624
Recent trends in the Exploration of Colossal Magneto Resistance ManganitesB. Raveau, A. Maignan, V. Caignaert and Ch. Simon
Laboratoire CRISMAT, URA 1318 du CNRS, ISMRA et Université de Caen, 6 boulevard du Maréchal Juin, 14050 Caen cedex, France
The recent developments of the colossal magnetoresistance (CMR) properties of the manganites Ln1-xAxMnO3 (A3 = Ca, Sr, Ba) are presented herein. Two types of oxides must be distinguished : type I oxides that display a FMM-PMI transition obtained for 0.2<x<0.5 and type II oxides x = 0.50 that exhibit an AFMI-FMM transition. Two key factors govern the CMR properties of these materials : the average size of the interpolated cations and the hole carrier density [Mn(III).Mn(IV) mixed valence]. The doping of the Mn sites by various cations M = Al, Ga, In, Sn, Ti, Mg, Fe is also studied showing spectacular results for magnesium and iron. The role of the structure is also discussed.
© EDP Sciences 1997