title: Transport and accumulation of spin anisotropy.
abstract: We show that spin anisotropy can be transferred to an isotropic system by transport of a spin-quadrupole moment. We derive the quadrupole moment current and continuity equation and study a spin-valve structure consisting of two ferromagnets coupled to a quantum dot probing an impurity spin. The quadrupole backaction on their coupled spin results in spin torques and anisotropic spin relaxation which do not follow from standard spin-current considerations. We demonstrate the detection of the impurity spin by charge transport and its manipulation by electric fields.
authors.affiliation: Peter Grünberg Institut, Forschungszentrum Jülich & JARA Jülich Aachen Research Alliance, D-52425 Jülich, Germany.
authors.forename: Michael M E
authors.initials: MM
authors.lastname: Baumgärtel
authors.forename: Michael
authors.initials: M
authors.lastname: Hell
authors.forename: Sourin
authors.initials: S
authors.lastname: Das
authors.forename: Maarten R
authors.initials: MR
authors.lastname: Wegewijs