Ferromagnetic structurally disordered ZnO implanted with Co ions

We present superparamagnetic clusters of structurally highly disordered Co–Zn–O created by high fluence Co ion implantation into ZnO _0001_ single crystals at low temperatures. This secondary phase cannot be detected by common x-ray diffraction but is observed by high-resolution transmission electron microscopy. In contrast to many other secondary phases in a ZnO matrix, it induces low-field anomalous Hall effect and is thus a candidate for magnetoelectronics applications.