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Abstract Thin ferromagnetic films possessing perpendicular magnetic anisotropy derived from the crystal lattice can deliver the requisite magnetocrystalline anisotropy density for thermally stable magnetic memory and logic devices at the single-digit-nm lateral size. Here, we demonstrate that an epitaxial synthetic antiferromagnet can be formed from L10 FePd, a candidate material with large magnetocrystalline anisotropy energy, through insertion of an ultrathin Ir spacer. Tuning of the Ir spacer thickness leads to synthetic antiferromagnetically coupled FePd layers, with an interlayer exchange field upwards of 0.6 T combined with a perpendicular magnetic anisotropy energy of 0.95 MJ/m3 and a low Gilbert damping of 0.01. Temperature-dependent ferromagnetic resonance measurements show that the Gilbert damping is mostly insensitive to temperature over a range of 20 K up to 300 K. In FePd|Ir|FePd trilayers with lower interlayer exchange coupling, optic and acoustic dynamic ferromagnetic resonance modes are explored as a function of temperature. The ability to engineer low damping and large interlayer exchange coupling in FePd|Ir|FePd synthetic antiferromagnets with high perpendicular magnetic anisotropy could prove useful for high performance spintronic devices.

Magnon scattering enables non-linear microwave devices, such as frequency selective limiters and signal to noise enhancers. It may also impact information transfer within spintronic devices. Here, a quantitative understanding of magnon processes in thin films is developed using micromagnetic simulations, in combination with newly developed analytic theory and experimental data. A technique for calculating the number of magnons at each frequency and wavevector as a function of external input such as power and frequency is identified. It is shown that, near the nonlinear threshold, the dominant parametrically excited magnon pairs are those with minimal group velocity and the correct energy. These results complement Brillouin Light Scattering experiments and indicate a path for wavevector-modulated magnon production based only on simulated results and/or analytic theory, a desirable goal for information transfer and communication.