<span style="font-size: 22.5pt;mso-bidi-font-size:15.5pt;font-family:"Times New Roman","serif"; mso-bidi-font-weight:bold">Dielectric relaxation studies of 100 MeV Ni⁵⁸<span style="font-size:17.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman","serif"; mso-bidi-font-weight:bold"> <span style="font-size:22.5pt;mso-bidi-font-size: 15.5pt;font-family:"Times New Roman","serif";mso-bidi-font-weight:bold">ion irradiated kapton-H polyimide film </span></span></span>

Abstract

654-659<span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" arial","sans-serif""="">Kapton -H polyimide samples of thickness 12.5<span style="font-size:14.5pt; mso-bidi-font-size:7.5pt;font-family:" arial","sans-serif";mso-fareast-font-family:="" hiddenhorzocr"="">µ<span style="font-size:14.5pt;mso-bidi-font-size:7.5pt; font-family:HiddenHorzOCR;mso-hansi-font-family:Arial;mso-bidi-font-family: HiddenHorzOCR">m <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:" arial","sans-serif""="">have been irradiated with 100 MeV Ni58 ion beam with fluences 6.295 <span style="font-size:12.0pt;mso-bidi-font-size: 5.0pt;font-family:" times="" new="" roman","serif""="">×<span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" arial","sans-serif""="">1011 and 2.57 <span style="font-size:12.0pt;mso-bidi-font-size:5.0pt;font-family: " times="" new="" roman","serif""="">× 1012<span style="font-size: 12.5pt;mso-bidi-font-size:5.5pt;font-family:" times="" new="" roman","serif""=""> ions/cm2 .<span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family: " arial","sans-serif""="">The dielectric constant/loss investigations have been measured from 30 to 240°C<span style="font-size:19.5pt;mso-bidi-font-size: 12.5pt;font-family:" times="" new="" roman","serif""=""> <span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" arial","sans-serif""="">for different frequencies ranging from 100Hz to 3 MHz. The nature of Ɛ'-<i style="mso-bidi-font-style: normal">T curve in low temperature region (30-70°C) is mainly governed by γ-relaxation. The dielectric loss peak at 60°C is in conformity with this relaxation. The dielectric constant in the temperature range 70-180°C is mainly governed by dipolar and space charge relaxations. The new energy <span style="font-size:13.0pt;mso-bidi-font-size: 6.0pt;font-family:HiddenHorzOCR;mso-hansi-font-family:Arial;mso-bidi-font-family: HiddenHorzOCR">trap <span style="font-size:15.0pt;mso-bidi-font-size: 8.0pt;font-family:" arial","sans-serif""="">due to the formation or free radicals by high-energy ion irradiation, contributes significantly towards space charge relaxation. In this temperature region,Ɛ<span style="font-size:13.5pt;mso-bidi-font-size: 6.5pt;font-family:" times="" new="" roman","serif""="">' <span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" arial","sans-serif""="">or high flux irradiated samples is more than low flux irradiated samples. In high temperature region (180-240°C) the increase in Ɛ<span style="font-size:14.0pt; mso-bidi-font-size:7.0pt;font-family:" times="" new="" roman","serif""=""> ' with temperature is mainly due to interfacial polarization, which arises due to formation or new phases by irradiation. The loss maximumin Ɛ "- <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:" arial","sans-serif""="">T <span style="font-size:15.0pt; mso-bidi-font-size:8.0pt;font-family:" arial","sans-serif""="">curve at 240°C confirms the presence or this relaxation. </span