Weak charge-ordering behavior in phase separated (Ln1/3Sm2/3)2/3Ca1/3MnO3 (Ln=Pr and La) manganites

Saket Asthana (1, 2) , Joonghoe Dho (2) , Dhirendra Bahadur (1, 3)

1 Department of Metallurgical Engineering and Materials Science
2 Department of Physics
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

We have studied a weak charge-ordering behavior in phase separated (Ln1/3Sm2/3)2/3Ca1/3MnO3 (Ln=Pr and La) manganites with same hole doping but slightly different tolerance factors. The M(T) and ρ(T) curves of the Pr-sample showed an anomaly caused by a weak charge-order (CO) transition at not, vert, similar210 K, while that of La-sample did not. However, the La-sample displayed a weak anomaly related to the CO instability in the derivative curve of the temperature dependent magnetoresistance. This result is understood on the basis that the CO phase in La-sample is partly suppressed by a large magnetic field of not, vert, similar80 kOe, while in Pr-sample it is not collapsed in that field scale. Our data support the existence of charge-ordering, electronic phase separation and a field-induced reduction of weak CO instability for La-sample, which can contribute towards high MR especially at lower temperatures due to partial melting of CO phase and/or percolation behavior.

Mots clés: Manganites; Magnetoresistance; Colossal magnetoresistance; Electronic phase separation

Domaines: Matériaux

Saket Asthana, Joonghoe Dho, Dhirendra Bahadur. Weak charge-ordering behavior in phase separated (Ln1/3Sm2/3)2/3Ca1/3MnO3 (Ln=Pr and La) manganites. Solid State Communications, 2007, 143 (11-12), pp.522-526. ⟨10.1016/j.ssc.2007.07.008⟩. ⟨hal-00179960⟩