Ultra-fast fault current limiter based on La-Ca-MnO3 thin films

A fast fault current limiter based on La 0.67 Ca 0.33 MnO 3 films and designed in the shape of a co-planar 50 Q impedance transmission line is presented. The limiter is intended to protect the input circuits of high frequency wide band electronic devices. The operation of this limiter is based on fast electroresistance phenomenon in manganites. The main behaviour of this phenomenon at temperatures close to its phase transition temperature T m was studied. It was demonstrated that the specific resistance of the film decreases exponentially with increase of electric field. The experimental results of losses induced by the fault current limiter in a 50 Ω impedence transmission line for nonlimiting and limiting regimes are presented. The phenomenological relation between input and output voltage transients' amplitudes of transmission lines protected by such limiter is obtained.