Nanostructured Manganite Films as Protectors Against Fast Electromagnetic Pulses

The effects of strong electric fields on the resistivity of thin nanostructured La-Ca(Sr)-Mn-O films, deposited on lucalox substrates by the metal-organic chemical vapor deposition technique, are investigated using electrical pulses with a pulselength of 5 ns and an amplitude of up to 500 V. The influence of the chemical composition of these films is analyzed to determine the optimal conditions for their use as protectors against fast electromagnetic pulses (EMPs) when operating at the temperature of liquid nitrogen as well as at room temperatures. It is shown that by changing the doping material (using Ca instead of Sr), it is possible to reduce the threshold voltage in these films and to obtain better limiting characteristics at lower amplitudes of such pulsed electric fields.