Magnetoacoustic Nonlinearity in Piezoelectric - Nickel Film Binary Structure
S.N.Karpachev, A.S.Andreenko, K.S.Chamorovskii, A.I.Yafasov (Faculty of Physics, Moscow State University, Moscow, Russia)
Acoustic wave propagation in magnetics with strong magnetoelastic coupling is accompanied by a number of nonlinear effects. An investigation of these effects provides information about effective magnetic fields determining magnetic structure of a substance, domain structure, and the degree of the magnetic and structural heterogeneity. The surface acoustic waves (SAW) propagation in a binary system consisting of the Ni film (13 mm long, 12 mm wide, and 2 um thick) deposited onto the YZ-LiNbO3 substrate was studied in this work. The system was exposed to an external magnetic field varying within the range from -250 to +250 Oe. The dependence of the amplitude of SAW and its harmonics on the magnitude and direction of the magnetic field was studied at frequencies of 15, 30 and 45 MHz. Magnetoacoustic resonance at the frequency of 30 MHz was observed in a magnetic field of ~ 5-10 Oe directed along the easy-magnetization axis of the film. The dependence of the domain structure of the film on the magnitude and direction of the external magnetic field was also studied. Variations in the SAW amplitude were found to correlate with changes in the domain structure of the film.
Section : 2