Transport, magnetic, internal friction, and Young's modulus in the Y-doped manganites La0.9−xYxTe0.1MnO3

The resistivity, magnetization, internal friction, and Young's modulus for the polycrystalline samples La0.9−xYxTe0.1MnO3 (x=0x=0, 0.05, 0.10 and 0.15) have been investigated. All samples have rhombohedral crystallographic structure with the space group R3¯C. The Curie temperature TC of the studied samples decreases with increasing Y-doping level. For the samples with x=0,0.05x=0,0.05 and 0.10, the temperature dependence of the resistivity ρ(T) exhibits two metal–insulator transitions (MIT) at Tp1 (which is close to its Curie temperature TC) and Tp2 (which is below Tp1). When the doping level to 0.15, these two MIT temperatures are suppressed and an upturn at low temperatures below T* is observed from the ρ(T) curve. A change of Young's modulus E is observed in the vicinity of TC accompanied by a broad peak of the internal friction Q−1 for all studied samples. The values of the relative Young's modulus ΔE increase with increasing Y-doping level at the low temperatures. These results are discussed in terms of the local Jahn–Teller (JT) distortion by the substitution of smaller Y3+ ions for larger La3+ ions and the increased bending of the Mn–O–Mn bond with decreasing the average ionic radius of the A-site element 〈rA〉 and the tolerance factor t, resulting in the narrowing of the bandwidth, the decrease of the mobility of eg electrons and the weakening of double-exchange (DE) interaction.

XRD patterns of the compound La0.9−xYxTe0.1MnO3 (x=0x=0, 0.05, 0.10, 0.15).Figure optionsDownload as PowerPoint slide