Room temperature magnetoresistance in Ln2/3A1/3MnO3 manganites

✍ Scribed by D. Zhu; A. Maignan; M. Hervieu; S. Hébert; B. Raveau

• Book ID: 104166268
• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 232 KB
• Volume: 127
• Category: Article
• ISSN: 0038-1098
• DOI: 10.1016/s0038-1098(03)00505-2

✦ Synopsis

The investigation of the manganites La 2=3 2 x Pr x Sr 1/3 MnO 3 , La 2/3 Sr 1=3 2 x Ca x MnO 3 and La 2=3 þ x Ca 1=3 2 2x Ag x MnO 3 , which all exhibit Mn 3þ :Mn 4þ ¼ 2, shows that it is possible to reach high magnetoresistance at room temperature, up to 21% under 1.2 T. These materials are compared to La 5/6 Ag 1/6 MnO 3 which corresponds to the same Mn 3þ :Mn 4þ ratio and exhibits a magnetoresistance of 25% in this field. An interesting feature deals with the value of the insulator -metal transition temperature T IM ; often higher than T C ; especially for Ag-based compounds. It is suggested that the latter results either from a better oxygenation of the surface of the grains or from a migration of silver toward the surface.