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We report the first observation of a transient all electric field induced magnetic anisotropy in a thin film metallic ferromagnet. We generate the anisotropy with a strong (approximately 10(9) V/m) and short (70 fs) E-->-field pulse. This field is large enough to distort the valence charge distribution in the metal, yet its duration is too brief to change the atomic positions. This pure electronic structure alteration of the sample generates a new type of transient anisotropy axis and strongly influences the magnetization dynamics. The successful creation of such an anisotropy opens the possibility for all E-->-field induced magnetization reversal in thin metallic films--a greatly desired yet unachieved process.

We propose schemes of reversing the magnetization of a ferromagnet by electric fields alone, without charge or spin currents or external magnetic fields. The switching is triggered by picosecond manipulation of the atomic positions or subpicosecond distortion of the valence charge distribution, which through spin-orbit coupling modifies the magnetic anisotropy. We discuss how such time-even anisotropies can be used to switch the time-odd magnetization for in-plane and out-of-plane magnetization directions. In all cases the switching process is completely determined by the appropriately chosen orientation, magnitude, and temporal length of the electric field created by a voltage or photon pulse.