Abstract

The possibility of the formation of a La_{1 – 2x}Bi_xSr_xMn_{1 – y}Ni_yO_{3 + δ} solid solution (x = 0.15, 0.25, y = 0.0–0.4) and the effect produced by the method of synthesis on its characteristics have been studied. Single-phase compounds with a rhombohedral structure have been obtained at y ≤ 0.2. A further increase in Ni²⁺ content leads to the formation of some additional phases, namely, NiO, Bi_7.72Mn_0.28O_12.14, or Bi_1.72Sr_0.53O₃. The thermal expansion coefficients (TECs) of La_0.7Bi_0.15Sr_0.15MnO_3.22 and La_0.7Bi_0.15Sr_0.15Mn_0.9Ni_0.1O_3.17 coincide with each other and equal 12 × 10^–6 K^–1. The electrical conductivities of the samples synthesized by the citrate–nitrate (cn) and coprecipitation (cp) methods are one order of magnitude higher than for solid-state (ss) synthesis due to smaller sizes of particles (1–5 µm). The presence of impurities promotes an abrupt decrease in the electrical conductivity at temperatures below 773 K. The change of pO₂ within a range of 10^—7–0.21 atm has no effect on the overall electrical conductivity of the samples.

中文翻译：

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La 1 – 2x Sr x Bi x Mn 1 – y Ni y O 3 +δ（x = 0.15，0.25，y = 0.0–0.4）的合成，结构和性质

摘要

La _{1 – 2 x} Bi _x Sr _x Mn _{1 – y} Ni _y O _{3 +δ}固溶体（x  = 0.15、0.25 ，y = 0.0-0.4）形成的可能性以及合成方法产生的效果对其特性进行了研究。已经在得到具有菱形结构的单相化合物ý ≤0.2。Ni ²⁺含量的进一步增加导致形成一些附加相，即NiO，Bi _7.72 Mn _0.28 O _12.14或Bi _1.72 Sr _0.53 O₃。La _0.7 Bi _0.15 Sr _0.15 MnO _3.22和La _0.7 Bi _0.15 Sr _0.15 Mn _0.9 Ni _0.1 O _3.17的热膨胀系数（TECs）彼此一致，并且等于12×10 ^–6 K ^–1。通过柠檬酸盐-硝酸盐（cn）和共沉淀（cp）方法合成的样品的电导率比固态（ss）合成的样品高一个数量级，这是因为颗粒尺寸较小（1-5 µm）。杂质的存在会导致在773 K以下的温度下电导率突然下降。p O ₂在10 ^-7 -0.21 atm的范围内对样品的总电导率没有影响。