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用固相反应法制备了La0.4Ca0.6Mn1-xCrxO3(x=0.00,0.08)多晶样品,通过XRD谱、M~T曲线、ρ~T曲线、Lnρ-T-14曲线,研究Cr3+替代Mn3+对La0.4Ca0.6MnO3电荷有序相及电输运性质的影响.实验结果表明:Cr3+替代Mn3+对La0.4Ca0.6MnO3电荷有序相影响明显,但对电输运性质影响不明显.原因是Cr3+替代Mn3+破坏了CE型反铁磁的自旋序从而引起电荷序被破坏,由于Cr3+与Mn4+具有相同的电子结构,Cr3+替代Mn3+虽然破坏了体系的电荷序,但是仅形成小的铁磁区,磁结构仍为在反铁磁背景下存在少量铁磁成分,掺杂样品与母体样品的电输运性质都符合Mott的可变程跃迁模型ρ=ρ0exp(T0/T)1/4.
The La0.4Ca0.6Mn1-xCrxO3 (x = 0.00,0.08) polycrystalline samples were prepared by the solid-state reaction method. The XRD, M ~ T curve, ρ ~ T curve and Lnρ-T- On the order and charge transport properties of La0.4Ca0.6MnO3 charge.The experimental results show that the effect of Cr3 + substitution Mn3 + on the charge ordered phase of La0.4Ca0.6MnO3 is obvious, but the effect on the charge transport properties is not obvious The substitution of Cr3 + for Mn3 + destroys the CE-type antiferromagnetic spin sequence, which leads to the destruction of the charge sequence. Since Cr3 + has the same electronic structure as Mn4 +, Cr3 + replaces Mn3 +, although it destroys the charge sequence of the system, The magnetic structure is still a small amount of ferromagnetic composition in the antiferromagnetic background. The electrical transport properties of the doped samples and the matrix samples are in accordance with Mott’s variable-state transition model ρ = ρ0exp (T0 / T) 1/4.