Program Highlights

Ferroelectrically Controlled Magnetism

S. Sahoo, S. Polisetty, C.-G. Duan, Sitaram S. Jaswal, E. Y. Tsymbal, and Ch. Binek
Nebraska MRSEC

A new path in electrically controlled magnetism has been explored within this MRSEC collaborative work (S. Sahoo et al., Phys. Rev. B 76, 092108 (2007). Remarkably, here electric control of magnetic states relies neither on conventional magnetoelectric materials nor on bulk multiferroics or spin torque effects. We studied a ferromagnetic (FM)/ferroelectric (FE) Fe/BaTiO₃ heterostructure exploiting strong magneto-elastic strain coupling. Using such a simple and prototypical materials combination makes our heterostructure very attractive for future spintronic applications where FM/FE systems serve as fundamental building blocks of more complex devices. Our results obtained on MBE grown Fe thin films deposited on a BaTiO₃ single crystal show up to a 120% strain-induced coercivity change in the magnetic hysteresis of the Fe layer when driving the BaTiO₃ through a sequence of reversible structural phase transitions by thermal means. Similarly, piezoelectrically induced strain affects the magnetic anisotropy of the Fe film, demonstrating up to 20% electrically controlled coercivity changes of the magnetic hysteresis. This coercivity change is significantly larger than those recently reported in FePt and FePd thin films immersed in an electrolyte making our all solid state structure highly attractive for device applications.
This research is supported by the National Science Foundation, Division of Materials Research, Materials Research Science and Engineering Program, Grant 0213808.