title: Interface control of the magnetic chirality in CoFeB/MgO heterostructures with heavy-metal underlayers.
abstract: Recent advances in the understanding of spin orbital effects in ultrathin magnetic heterostructures have opened new paradigms to control magnetic moments electrically. The Dzyaloshinskii-Moriya interaction (DMI) is said to play a key role in forming a Néel-type domain wall that can be driven by the spin Hall torque. Here we show that the strength and sign of the DMI can be changed by modifying the adjacent heavy-metal underlayer (X) in perpendicularly magnetized X/CoFeB/MgO heterostructures. The sense of rotation of a domain wall spiral is reversed when the underlayer is changed from Hf, Ta to W and the strength of DMI varies as the filling of 5d orbitals, or the electronegativity, of the heavy-metal layer changes. The DMI can even be tuned by adding nitrogen to the underlayer, thus allowing interface engineering of the magnetic texture in ultrathin magnetic heterostructures.
authors.affiliation: National Institute for Materials Science, Tsukuba 305-0047, Japan.
authors.forename: Jacob
authors.initials: J
authors.lastname: Torrejon
authors.affiliation: National Institute for Materials Science, Tsukuba 305-0047, Japan.
authors.forename: Junyeon
authors.initials: J
authors.lastname: Kim
authors.affiliation: National Institute for Materials Science, Tsukuba 305-0047, Japan.
authors.forename: Jaivardhan
authors.initials: J
authors.lastname: Sinha
authors.affiliation: National Institute for Materials Science, Tsukuba 305-0047, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Mitani
authors.affiliation: National Institute for Materials Science, Tsukuba 305-0047, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: 1] Center for Spintronics Integrated Systems, Tohoku University, Sendai 980-8577, Japan [2] Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Michihiko
authors.initials: M
authors.lastname: Yamanouchi
authors.affiliation: 1] Center for Spintronics Integrated Systems, Tohoku University, Sendai 980-8577, Japan [2] Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan [3] WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohno