Coercivity change in an FePt thin layer in a Hall device by voltage application

The coercivity (H(c)) of a perpendicularly magnetized FePt layer was modulated by applying the voltage (V(app)) to a Hall device through MgO and Al-O insulating layers. A change in similar to 40 Oe in H(c) was observed by changing V(app) from -13 to 13 V. From the quantitative analysis of the voltage effect on H(c), the change in the anisotropy energy by voltage application was evaluated to be 18.6 fJ/V m, which was of the same order as the theoretical prediction. The role of the MgO layer for the voltage effect was also discussed. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3595318]