Electrical Control of the Magnetic State of Fe

Abstract

Magneto-electric coupling offers a new pathway to information storage in magnetic memory devices. This phenomenon has been observed in various materials ranging from insulators to semiconductors. In bulk metallic systems, magneto-electric coupling has been disregarded as the electric field cannot enter bulk metals. In this work, we show that a substantial magneto-electric coupling exists in metallic Fe nano-islands grown on Cu(111). Using the electric field in the tunnel junction of a scanning tunneling microscope, the magnetic order parameter and the crystal structure of Fe was changed on the nanometer scale. This allows high density nonvolatile information storage by means of magneto-electric coupling in a simple metallic system.

Magnetoelectric coupling at metal surfaces

“…The experimental finding of MEC and the theoretical simulations ( Fig. 4.1 to 4.7) are published results [38,39,40]. Fe is known for its large number of different phases.…”

Electric Field Control of Fe Nano Magnets: Towards Metallic Nonvolatile Data Storage Devices

“…Our theoretical calculations predict that a huge electric field of the order of 10 9 V/m is needed to trigger the crystal-lographic and magnetic phase transition. 11,12) An STM setup can produce such large electric fields: Since the gap distance between the STM probe tip and the sample surface is smaller than 1 nm, a bias voltage of the order of 1 V generates an electric field of more than 10 9 V/m. In this study, we applied electric fields of 10 6 -10 10 V/m to the Fe nano-islands.…”

“…Applying a high electric field to the Fe nano-islands induces subtle displacements of the atomic positions, changing the crystalline and the magnetic order simultaneously. 11,12) Statistical experiments showed that the polarity of the electric field allows selective switching from one phase to the other and vice versa. This new finding of a magnetoelectric coupling at the metallic Fe surface will rise new hope towards an electric field controlled magnetic datastorage device.…”

Metastable fcc-Fe film epitaxially grown on Cu(100) single-crystal underlayer

“…3,4 Thin fcc-Fe films have been prepared through hetero-epitaxial growth on fcc-Cu underlayers of (100) and (111) orientations. [5][6][7][8][9][10][11] However, the metastable structure tends to transform into more stable bcc structure with increasing the thickness. There are few reports on the preparation of fcc-Fe epitaxial films with moderate thicknesses.…”