The effect of Mn-site doping on the magnetotransport properties of CMR manganites

• Published in: Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences physical, and engineering sciences, 1998-07, Vol.356 (1742), p.1635-1659
• Main Authors: Maignan, A., Damay, F., Barnab é, A., Martin, C., Hervieu, M., Raveau, B.
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Chromium; Doping; Electrical resistivity; Ferromagnetism; Insulator-Metal; Magnetic fields; Magnetization; Magnetoresistance; Manganite; Materials; Mn-Site Doping; Perovskites; Series convergence; Transition temperature
• ISSN: 1364-503X; 1471-2962
• DOI: 10.1098/rsta.1998.0239

Doping of the Mn-site in Ln1-yAyMn1-xMxO3 manganites has been extensively investigated. For the manganites exhibiting a Curie temperature (Tc) these substitutions depress Tc. However, the effect on Tc is doping-element dependent. It decreases from dTc/dx = -25 K %-1 for M = Fe down to dTc/dx∼0 K %-1 for M = Cr in the series Sm0.56Sr0.44Mn1-xMxO3. The peculiar role of chromium doping is also shown in the case of the charge-ordered Ln0.5Ca0.5MnO3 substituted manganites that are characterized by low average cationic size on the A-site and cationic size mismatch. For the latter, metal-insulator transitions together with CMR properties are induced by Cr and to a smaller extent by Co and Ni. The hindering of the charge-ordering establishment by these 'impurity effects' is also observed in the case of the two-dimensional manganites La0.5Sr1.5MnO4 and LaSr2Mn2O7. The highest efficiency of Cr among all doping elements may be ascribed to the similar t32g electronic configurations of Cr3+ and Mn4+ which allows a double-exchange between the Cr3+ and Mn3+ species.