Dielectric characteristics of substituted M-type strontium hexaferrite crystals and their modifications on swift heavy ion irradiation

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• 作者：Balwinder Kaur ; Monita Bhat ; F. Licci ; Ravi Kumar ; K.K. Bamzai ; P.N. Kotru
• 关键词：Defects ; Irradiation ; Dielectric behaviour ; Polaron interaction ; Hexaferrite
• 刊名：Materials Chemistry and Physics
• 出版年：2007
• 出版时间：15 June 2007
• 年：2007
• 卷：103
• 期：2-3
• 页码：255-263
• 全文大小：1131 K

文摘

Dielectric behaviour of flux grown substituted crystals bearing composition SrGa_xIn_yFe_12−(x+y)O₁₉ (x = 5, 7, 9; y = 0.8, 1.3, 1.0) is reported. Variation of dielectric constant (^/), dielectric loss (tan δ) and ac conductivity (σ_ac) with temperature in the range 30–500 °C under the frequency of the applied ac field in the range 1–10⁴ kHz for all the varied compositions are analyzed and explained. Swift heavy ion irradiation effects on these parameters are investigated. On irradiation the crystals show changes in the values of dielectric constant (^/), dielectric loss (tan δ) and ac conductivity (σ_ac). The frequency variation of ^/ and tan δ is explained by Koop's phenomenological theory and hopping frequency of electrons between Fe²⁺ and Fe³⁺ on octahedral sites for both irradiated and unirradiated crystals.