Thin manganite films for fast fault current limiter applications

The electrical transport properties of thin films of perovskite manganites deposited on various substrates are summarised and discussed, focusing on the exploitation of their features for fast fault current limiter applications. The influence of strong electric fields on the resistivity of thin La0.67Ca0.33MnO3 and La0.83Sr0.17MnO3 films was investigated using nanosecond duration and subnanosecond rise time electrical pulses. It was obtained that a strong electric field induces a substantial resistance decrease in the films at a threshold electric field value. The ratio of the film resistance at low electric field and at strong electric field is the highest for polycrystalline films prepared on lucalox substrates. It was demonstrated that a limiter operating at room temperature and having 10 V threshold voltage, with 0.7 dB initial losses in the non-limiting regime and 6 dB attenuation in the limiting regime could be designed using 100–400 nm thickness polycrystalline manganite films. The limiter for low temperature operation having the same initial losses could be designed with the following parameters: 4 V threshold voltage and 8 dB attenuation in the limiting regime.