RF electrical pulse modulation using magnetically triggered thin manganite films

Abstract

The modulation of the amplitude of RF electrical pulses was realized by applying external magnetic fields on 20 nm thick thin epitaxial Lao.83Sro.i7Mn03 films grown by the MOCVD method. The thin film coplanar two-terminal device was connected in parallel to a 50 Q impedance transmission line and mounted inside the bore of a pulsed magnetic field coil. Single 5.5 V amplitude electrical pulses, having pulse lengths of 10 ns and rise times of 250 ps were transmitted through the line and were synchronized with half-sinus shape magnetic field pulses with a pulse length of 0.6 ms at the moment in time that it reached its maximal value (13 T). Measurements were performed over temperatures ranging from 200K to 300K. The attenuation (Z) of the pulse amplitude realized by this method, when the distance between electrodes of two-terminal coplanar device and their width was 50 urn and 3 mm, respectively, depended on its temperature and had a maximum (2 dB) at 280-290 K. It was concluded that the best regime to modulate signals with pulse lengths of 2-10 ns can be realized if the current density through the manganite film does not exceed 10 - 3-10 A/cm .