熱激勵去極化電流(thermally stimulated depolarization currents, 簡寫為TSDC或TSC)是電介質(zhì)材料在受熱過程中建立極化態(tài)或解除極化態(tài)時所產(chǎn)生的短路電流。基本方法是將試樣夾在兩電極之間,加熱到一定溫度使樣品中的載流子激發(fā),然后施加一個直流的極化電壓,經(jīng)過一段時間使樣品充分極化,以便載流子向電極漂移或偶極子充分取向,隨后立即降溫到低溫,使各類極化“凍結(jié)",然后以等速率升溫,同時記錄試樣經(jīng)檢流計短路的去極化電流隨溫度的變化關(guān)系,即得到TSDC譜。通過TSDC譜研究介質(zhì)材料中偶極子和可動離子的性質(zhì)、激活能(或陷阱深度)、以及弛豫時間(壽命)等。
General FeaturesAll TSDC (Thermal Stimulated Depolarization Current) measurements are supported by computer control and Windows-based software WinTSDC. It operates the polarization voltage source, the polarization/depolarization mode switches, the high sensitive and fast electrometer for sensing the depolarization current and several temperature control systems. Nearly any kind of TSDC experiment can be programmed by a flexible experiment set-up procedure. The experiment is defined by a series of time intervals. During each time interval, the polarization voltage and temperature is either defined as fixed value or with a continuously change in time (ramp). The system may be switched in each time interval between the polarization and depolarization current measurement mode. In addition to this general experiment set-up mode, predefined set-ups like e. g. batch modes for series of TSDC sweeps with different heating rates are supported.The basic TSDC parameters, like depolarization current as a function of temperature are evaluated and displayed graphically in single or multicurve representation and exported numerically. In another representation, the experiment state defined by polarization voltage, temperature and depolarization current is shown as a function of time.Optional Thermal WindowingIn addition to the standard TSDC functions, the thermal windowing technique can be performed by the TSDC system, which is requiring additional experiment conditions and optional software.It supports data manipulation functions like shifting, deleting of data points, and confining and smoothing of data curves. The main function of this software is the evaluation of relaxation maps from a thermal windowing experiment. The sample polarization is calculated by numerical integration from the measured depolarization current. Several procedures for integration and base line corrections are supported. After the conversion of the polarization and depolarization current into the relaxation time, the common relaxation maps are created. They show the single Debye relaxation modes in several representations like e. g. Arrhenius or a free energy diagram. Several curve fitting model functions like Arrhenius, Vogel Fulcher and Williams Landel Ferry (WLF) for the relaxation time data are supported.
極化電壓 | ±1kV |
電流量程 | 10fA~20mA |
溫度范圍 | -160 ~400 ℃ |
加熱速度 | 0.01~ 30 ℃/min |
冷卻速度 | 0.01~ 30 ℃/min |
測量樣品種類 | 固體、液體、粉末 |
控制方式 | WinTSC全自動控制 |
• 自動電壓、電流測量• 可選多種獨立變量:時間、溫度、極化電壓、極化溫度、極化時間、升降溫速率等等• 提供多種測量模式–Thermal Stimulated Depolarization Current–Thermal Stimulated Polarization Current–Isothermal–Relaxation Map with partial isothermal polarization–Relaxation Map with partial polarization due to thermal window• 可選多種測量參數(shù):樣品電流、電流密度、電荷變化、介電常數(shù)變化• 可導(dǎo)出為ASCII格式,并可顯示為二維、三維圖象,兼容Windows XP系統(tǒng)
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