Spin wave propagation in ultrathin magnetic insulators with perpendicular magnetic anisotropy

Magnetic thin films with perpendicular magnetic anisotropy (PMA) offer opportunities for studying magnetostatic forward volume mode (MSFVM) spin waves with isotropic propagation. Here, we realize the full reciprocal MSFVM spin wave propagation in a 30-nm-thick manganese doped yttrium iron garnet (YIG) with PMA by only applying an external field of 5mT. The external magnetic field required for investigating the MSFVM spin waves in YIG is reduced by 34 times compared to the in-plane magnetized one. The spin wave group velocity and decay length are also investigated. Our finding paves the way for applications of isotropic magnonic computing systems and logic devices.