Effects of La and O deficiencies on AC & DC electrical conduction in La2Ti2O7 ceramics

IF 2.8 3区物理与天体物理 Q2 PHYSICS, CONDENSED MATTER

Physica B-condensed Matter Pub Date : 2025-09-05 DOI:10.1016/j.physb.2025.417777

Ravina Swami , A.K. Shukla , K. Sreenivas

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Abstract

Frequency and temperature dependence of dielectric properties of La₂Ti₂O₇ ceramics in the respective ranges (10⁻¹ to 10⁶ Hz) and (123–473 K) are analysed. Grain, grain boundary and electrode polarisation effects are distinguished from impedance Cole-Cole analysis. Temperature dependence of grain capacitance reveals the polar nature of La₂Ti₂O₇. Charge carriers contributing to the observed changes in the temperature dependent dielectric constant εʹ, alternating current (AC) and direct current (DC) conductivity are identified. Temperature independent Jonscher's power law exponent (s ∼ 1) and the low polarizability strength, explain the stability of εʹ in the low temperature range (<283 K). Interaction of holes and electrons in accordance with Rezlescu's model is reflected as a dip in the temperature dependent DC conductivity, and a diffused hump in εʹ(T) in the low temperature range (123–250 K). Electrical conductivity in the high temperature range (250–473 K) is attributed to hopping mechanism.

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La和O缺陷对La2Ti2O7陶瓷交直流导电性的影响

分析了La2Ti2O7陶瓷介电性能在10−1 ~ 106 Hz和123 ~ 473 K范围内的频率和温度依赖关系。晶粒、晶界和电极极化效应与阻抗Cole-Cole分析相区别。晶粒电容的温度依赖性揭示了La2Ti2O7的极性性质。确定了导致温度相关介电常数ε′、交流（AC）和直流（DC）电导率变化的载流子。温度无关的Jonscher幂指数（s ~ 1）和低极化强度解释了ε′在低温（<283 K）范围内的稳定性。根据Rezlescu的模型，空穴和电子的相互作用表现为随温度变化的直流电导率的下降，以及在低温范围(123-250 K) ε′(T)的扩散峰。高温范围（250 ~ 473 K）的电导率归因于跳变机制。

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来源期刊

Physica B-condensed Matter 物理-物理：凝聚态物理

CiteScore

4.90

自引率

7.10%

发文量

703

审稿时长

44 days

期刊介绍： Physica B: Condensed Matter comprises all condensed matter and material physics that involve theoretical, computational and experimental work. Papers should contain further developments and a proper discussion on the physics of experimental or theoretical results in one of the following areas: -Magnetism -Materials physics -Nanostructures and nanomaterials -Optics and optical materials -Quantum materials -Semiconductors -Strongly correlated systems -Superconductivity -Surfaces and interfaces