Brillouin-Mandelstam spectroscopy of stress-modulated spatially confined spin waves in Ni thin films on piezoelectric substrates

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:501

Article

Kargar, Fariborz^1,2  Balinskiy, Michael^1,2  Chiang, Howard^1,2  Chavez, Andres C.³  Nance, John³  Khitun, Alexander^1,2  Carman, Gregory P.³  Balandin, Alexander A.^1,2 

[1] Univ Calif Riverside, Dept Elect & Comp Engn, POEM Ctr, Riverside, CA 92521 USA

[2] Univ Calif Riverside, SHINES Ctr, Riverside, CA 92521 USA

[3] Univ Calif Los Angeles, Dept Mech & Aerosp Engn, Los Angeles, CA 92521 USA

关键词: Brillouin-Mandelstam spectroscopy;    Brillouin light scattering, magnons;    Spin waves;    Multiferroic;    Nickel;    Spintronic devices;    Quantum sensors;   

DOI  :  10.1016/j.jmmm.2020.166440

来源: Elsevier

【 摘 要 】

We report the results of micro-Brillouin-Mandelstam light scattering spectroscopy of thermal magnons in the two-phase synthetic multiferroic structure consisting of a piezoelectric [Pb(Mg1/3Nb2/3)O-3]((1-x))-[PbTiO3](x) (PMN-PT) substrate and a Ni thin film. The experimental data reveal the first two modes of the perpendicular standing spin waves (PSSW) spatially confined across the Ni thin film. A theoretical analysis of the frequency dependence of the PSSW peaks on the external magnetic field reveals the asymmetric boundary condition, Le. pinning, for variable magnetization at different surfaces of the Ni thin film. The strain field induced by applying DC voltage to PMN-PT substrate leads to a downshift of PSSW mode frequency owing to the magneto-elastic effect in Ni, and corresponding changes in the spin-wave resonance conditions. The observed non-monotonic dependence of the PSSW frequency on DC voltage is related to an abrupt change of the pinning parameter at certain values of the voltage. The obtained results are important for understanding the thermal magnon spectrum in ferromagnetic films and the development of the low-power spin-wave devices and quantum sensors.

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