The Mechanisms of Electric Field‐Induced Magnetic Bubble Domain Blowing

The surface tension of magnetic domain walls is one of the major forces that governs micromagnetism and prevents a spontaneous nucleation of magnetic topological defects like nanodomains and skyrmions. With the advent of magnetoelectric and multiferroic materials the problem of the magnetic topological defects stability should be revisited as the magnetic domain walls in the electric field acquire the effective negative surface energy. This additional micromagnetic energy term facilitates the electric‐field induced nucleation of the magnetic topological defect. In the present paper the experimental and theoretical studies reveal the mechanism of electric‐field blowing of the magnetic bubble domain: the electric field suppresses the energy barrier of the magnetic inhomogeneity nucleation and then pulls the opposite domain walls away from each other, thus inflating the bubble. The nature of unusually strong magnetoelectric effect in iron garnet films is studied both theoretically and experimentally. The electric field from the tip electrode eliminates the energy barrier of magnetic bubble domain nucleation, acting as a kind of “soap” lowering the domain wall surface tension, and then inflates the bubble with the chirality‐dependent Coulomb forces acting on its walls.