TY - JOUR

T1 - Electrical properties of n-conducting barium titanate ceramics over a wide temperature range under voltage load

AU - Preis, Wolfgang

N1 - Publisher Copyright: © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

PY - 2020/4/27

Y1 - 2020/4/27

N2 - Bulk and grain boundary resistivities as well as grain boundary capacitances of PTCR (positive temperature coefficient of resistivity) thermistors have been investigated as a function of voltage load and temperature ranging from 30 to 820 °C by application of impedance spectroscopy. In addition, current – voltage curves have been measured and the resistivities extracted from these dc measurements are in close agreement with those obtained from impedance spectroscopy. The resistance – temperature characteristics are typical for n-type barium titanate – based PTCR ceramics, viz. a steep increase of the grain boundary resistance above the Curie – temperature (PTCR effect) and decreasing resistance with increasing temperature in the NTC (negative temperature coefficient) regime above approximately 200 °C. The grain boundary capacitance shows a sharp peak at the Curie – temperature (around 120 °C) and obeys the Curie – Weiss law in the paraelectric state. Basically, the grain boundary resistivities decrease significantly under voltage load. However, at elevated temperatures (above 600–700 °C) this non-linear effect vanishes and linear ohmic (or even sub-ohmic) behavior can be observed. The electrical properties can be interpreted in terms of a modified double Schottky barrier model. Reasonable coincidence between simulated and measured current - voltage curves as well as grain boundary conductivities has been found in a wide temperature range (up to 800 °C) under high field conditions (up to an external field strength of 1000 V cm −1).

AB - Bulk and grain boundary resistivities as well as grain boundary capacitances of PTCR (positive temperature coefficient of resistivity) thermistors have been investigated as a function of voltage load and temperature ranging from 30 to 820 °C by application of impedance spectroscopy. In addition, current – voltage curves have been measured and the resistivities extracted from these dc measurements are in close agreement with those obtained from impedance spectroscopy. The resistance – temperature characteristics are typical for n-type barium titanate – based PTCR ceramics, viz. a steep increase of the grain boundary resistance above the Curie – temperature (PTCR effect) and decreasing resistance with increasing temperature in the NTC (negative temperature coefficient) regime above approximately 200 °C. The grain boundary capacitance shows a sharp peak at the Curie – temperature (around 120 °C) and obeys the Curie – Weiss law in the paraelectric state. Basically, the grain boundary resistivities decrease significantly under voltage load. However, at elevated temperatures (above 600–700 °C) this non-linear effect vanishes and linear ohmic (or even sub-ohmic) behavior can be observed. The electrical properties can be interpreted in terms of a modified double Schottky barrier model. Reasonable coincidence between simulated and measured current - voltage curves as well as grain boundary conductivities has been found in a wide temperature range (up to 800 °C) under high field conditions (up to an external field strength of 1000 V cm −1).

UR - https://pure.unileoben.ac.at/portal/en/publications/electrical-properties-of-nconducting-barium-titanate-ceramics-over-a-wide-temperature-range-under-voltage-load(0bda662e-196a-4ccb-b038-9b3a0f57190d).html

U2 - 10.1007/s10832-020-00208-5

DO - 10.1007/s10832-020-00208-5

M3 - Article

VL - 44.2020

SP - 173

EP - 182

JO - Journal of electroceramics

JF - Journal of electroceramics

SN - 1385-3449

IS - June

ER -