Nonlinear three-magnon scattering in low-damping La_(0.67)Sr_(0.33)MnO_(3)thin films

Three-magnon scattering,a nonlinear process in which a high-energy magnon splits into two low-energy magnons with energy and momentum conservation,has been widely studied in the magnonics community.Here,we report experimental observation of nonlinear three-magnon scattering in La_(0.67)Sr_(0.33)MnO_(3)thin films with low magnetic damping(~10^(-4))by all-electric and angle-resolved spin wave spectroscopy.The reflection spectra of the spin wave resonance with high-power excitation at Damon–Eshbach configuration demonstrate a scattering regime with gradual signal disappearance,where a magnon of Damon–Eshbach mode decays into two magnons of volume mode above the threshold power(-10 dBm)of the injected microwave.The nonlinear scattering is only allowed at low-field regime and the calculated dispersions of dipole-exchange spin wave claim the mechanism of allowed and forbidden three-magnon scattering.The films and heterostructures of La_(0.67)Sr_(0.33)MnO_(3)have been already demonstrated with rich physical phenomena and great versatility,in this work the nonlinear magnetic dynamics of La_(0.67)Sr_(0.33)MnO_(3)thin films is revealed,which offer more possibility for applications to oxide magnonics and nonlinear magnonic devices.

Optimization of cold spray additive manufactured AA2024/Al_(2)O_(3) metal matrix composite with heat treatment

In this study,the effects of annealing and solution aging heat treatment on the microstructure and mechanical properties of cold spray additive manufactured(CSAMed)AA2024/Al_(2)O_(3) composite were investigated.The results showed that both annealing and solution aging enhanced the interfacial bonding between the deposited AA2024 particles in the composite.The tensile properties of CSAMed AA2024/Al_(2)O_(3) composite were significantly improved by 13.8%for ultimate tensile strength and 47.8%for elongation after solution aging.Microstructural examination and fractographic analysis showed that the fracture mechanism between the adjacent AA2024 particles changed from brittle to ductile-dominant mode after heat treatment.However,the interfacial bonding between the AA2024 and Al_(2)O_(3) particles cannot be improved.For the improvement of mechanical properties,the solution aging was slightly better than annealing.In addition,low-temperature annealing greatly reduced the anisotropy of the mechanical properties of CSAMed AA2024/Al_(2)O_(3) composite.