title: Room-temperature ferromagnetism of all-epitaxial β-Fe-Ge/diamond-Ge/β-Fe-Ge trilayers.
abstract: We report on the first all-epitaxial ferromagnet/inorganic semiconductor/ferromagnet hybrid heterostructure that exhibits (i) a Ge barrier of diamond crystal structure, (ii) room-temperature ferromagnetic electrodes and (iii) very smooth interfaces. Both bottom- and top-Fe-Ge electrodes exhibit tiny in-plane magnetic anisotropies dominated by a magnetocrystalline contribution of six-fold symmetry originating from the hexagonal symmetry of the B82 (Ni2In) β-Fe-Ge phase. A key result is the absence of any magnetic coupling between these soft-magnetic electrodes for Ge barrier thickness as low as ~2.5 nm, which allows us to easily tune the parallel and antiparallel magnetic alignments by applying suitably small magnetic fields. This confirms the beneficial use of H-surfactant in order to drastically reduce the roughness of the Ge barrier, as revealed by our scanning tunneling microscopy and transmission electron microscopy measurements. This new all-epitaxial ferromagnet/semiconductor hybrid system appears, therefore, to be a promising candidate for the realization of magnetic tunnel junctions with a single crystal semiconductor barrier that are fully compatible with Si-based technology.
authors.affiliation: Institut de Science des Matériaux de Mulhouse, CNRS-UMR 7361, Université de Haute-Alsace, Mulhouse, France.
authors.forename: I
authors.initials: I
authors.lastname: Maafa
authors.forename: S
authors.initials: S
authors.lastname: Hajjar-Garreau
authors.forename: R
authors.initials: R
authors.lastname: Jaafar
authors.forename: D
authors.initials: D
authors.lastname: Berling
authors.forename: C
authors.initials: C
authors.lastname: Pirri
authors.forename: A
authors.initials: A
authors.lastname: Mehdaoui
authors.forename: E
authors.initials: E
authors.lastname: Denys
authors.forename: A
authors.initials: A
authors.lastname: Florentin
authors.forename: G
authors.initials: G
authors.lastname: Garreau