Author/Authors :
Xiao، نويسنده , , X. and Yuan، نويسنده , , S.L. and Wang، نويسنده , , Y.Q. and Ren، نويسنده , , G.M. and Miao، نويسنده , , J.H. and Yu، نويسنده , , G.Q. and Tian، نويسنده , , Z.M. and Liu، نويسنده , , L. and Chen، نويسنده , , L. and Yin، نويسنده , , S.Y.، نويسنده ,
Abstract :
Polycrystalline samples with formulas La2/3Ca1/3Mn1−xCrxO3 and La2/3+xCa1/3−xMn1−xCrxO3 ( x = 0 and 0.06) have been prepared. The structural, magnetic, electrical transport and magnetoresistance properties have been investigated comparatively. Compared with La2/3Ca1/3Mn1−xCrxO3, the magnetization and conductivity are enhanced in La2/3+xCa1/3−xMn1−xCrxO3 at low temperatures. It is found that there are two peaks in the resistivity versus temperature curve for La2/3Ca1/3Mn1−xCrxO3 and the additional peak disappears for La2/3+xCa1/3−xMn1−xCrxO3 ( x = 0.06 ). The experiment results are discussed by considering a variety of tolerance factors, the ratio of [Mn3+]/([Mn4+]+[Cr3+]), the effects of A-site radius and the A-site mismatch effect. We suggest that these peculiar effects of Cr doping could be the consequence of a possible double exchange interaction between Mn3+ and Cr3+.
Keywords :
D. Double exchange , B. Metal–insulator transition , D. Magnetization , A. Perovskite manganites
