SURFACE ACOUSTIC WAVE PROPERTIES OF RF SPUTTERED NICKEL FILMS ON LITHIUM NIOBATE.

RF sputtered thin films of nickel deposited on YZ-LiNbO//3 have been used for magnetically variables delay lines and oscillators. The rf sputtered films have shown a factor of three increase in velocity variation DELTA v/v and a factor of ten decrease in required magnetic bias field compared to similar thermally evaporated films. At 189 MHz a DELTA v/v of 0. 07% in a parallel field of 100 oe was observed. An approximate analytical estimate of DELTA v/v is developed based on a stress-induced perpendicular anisotropy which agrees well with measured results. The device was also operated as a convolver in order to study the nonlinearities in the film. An internal efficiency of minus 77 dbm was obtained for 189 MHz input signals parallel field of 200 oe.