MegaOhm extraordinary Hall effect in oxidized CoFeB

We report on the development of controllably oxidized CoFeB ferromagnetic films demonstrating the extraordinary Hall effect (EHE) resistivity exceeding 1 $\Omega $ cm and magnetic field sensitivity up to 10$^{6}$ $\Omega $/T. Such EHE resistivity is four orders of magnitude higher than that previously observed in ferromagnetic materials, while sensitivity is two orders larger than the best of semiconductors.