Abstract The temperature dependences of the resistivity ρ(T) of ceramic samples at x = 0.5, and y = 0, 0.02 and 0.10 are investigated in the temperature range of 5-300 K in magnetic field B up to 1 T. It was found that dependences ρ(T) with x = 0.5; y = 0.02, and 0.10 obey the Shklovskii–Efros-like variable-range hopping conductivity law This behavior is governed by generation of a soft Coulomb gap Δ ≈ 0.3 eV in the density of localized states, as well as a rigid gap ≈ 0.20 and 0.17 eV at y = 0.02 and y = 0.10, respectively. The obtained values of the rigid gap at y = 0.02 indicate the presence of charge ordering. It was shown that a decrease in the width of the rigid gap when y is increased, is accompanied by both a growing disorder attributed to the presence of Fe and a decrease in lattice distortions caused by charge ordering at y = 0.02. It is shown that the pre-exponential factor of resistivity follows the law where m changes from 9/2 at y = 0.02 to 5/2 at y = 0.10. This confirms that doping with Fe enhances microscopic disorder by introducing an additional fluctuating short-range potential. The calculated values of the carrier localization radius α ≈ 5.1 and 2.7 Å at y = 0.02 and y = 0.10, respectively, satisfy the condition for the formation of small polarons.

中文翻译：

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La1−xSrxMn1−yFeyO3 中的可变范围跳跃电导率 (x = 0.5; y = 0, 0.02, 0.1)

摘要 研究了在磁场 B 到 1 T 的 5-300 K 温度范围内，陶瓷样品在 x = 0.5 和 y = 0、0.02 和 0.10 处的电阻率 ρ(T) 的温度依赖性。依赖 ρ(T) 与 x = 0.5；y = 0.02，且 0.10 遵守 Shklovskii-Efros 类可变范围跳跃电导率定律 这种行为受局部态密度中软库仑间隙 Δ ≈ 0.3 eV 以及刚性间隙 ≈ 0.20 和分别在 y = 0.02 和 y = 0.10 处为 0.17 eV。在 y = 0.02 处获得的刚性间隙值表明存在电荷排序。结果表明，当 y 增加时刚性间隙的宽度减小，伴随着由于 Fe 的存在而导致的无序增长和由 y = 0.02 处的电荷排序引起的晶格畸变的减少。结果表明，电阻率的指数前因子遵循m从y=0.02时的9/2变化到y=0.10时的5/2的规律。这证实了掺杂 Fe 通过引入额外的波动短程电位来增强微观无序。在 y = 0.02 和 y = 0.10 处，载流子定位半径 α ≈ 5.1 和 2.7 Å 的计算值分别满足小极化子形成的条件。