1 / 1

Spin reorientation at the antiferromagnetic NiO(001)

Parallel domain correlation at interface. Co / NiO(001). Summary. AFM. FM. M. Ni XMLD. Co XMCD. Antiferromagnet, N é el temperature 523 K Spins lie in ferromagnetic {111} sheets along <112> directions {111} sheets are coupled antiferromagnetically

maree
Télécharger la présentation

Spin reorientation at the antiferromagnetic NiO(001)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Parallel domain correlation at interface Co / NiO(001) Summary AFM FM M Ni XMLD Co XMCD • Antiferromagnet, Néel temperature 523 K • Spins lie in ferromagnetic {111} sheets along <112> directions • {111} sheets are coupled antiferromagnetically • Strong rhombohedral compression along <111> axes (10-3) • Surface magnetic structure can differ from bulk structure=> bulk methods are of limited value for the understanding of interface effects • Clear evidence for parallel coupling between AFM and FM in Co/NiO, no indication of spin canting, ruling out spin-flop models • Exchange coupling is related to about 1 ML of uncompensated spins at the AFM surface H 3 possible "S" domains One of 4 "T" domains E [010] [010] E [001] _ <110> s s s _ <211> _ [±110] <121> [±110] [100] [100] <101> _ _ <112> _ <011> Single crystalline NiO (001) sample preparation : cleaved ex-situ annealed at 380 K in PEEM chamber Co (< 2 nm) deposited in-situ [010] [010] x' [100] [100] What causes correlation - exchange coupling at interface ? Nickeloxide interface magnetism NiO antiferromagnetic NiO interface ferromagnetic Co ferromagnetic XMLD XMCD XMCD NiO Co ~1 monolayer Domain structure of Co/NiO(001) [010] NiO Co [100] NiO Co/NiO • NiO interface structure is not bulklike! • (±110) walls disappear after Co deposition • AFM axis rotates in-plane along [±110] Co/NiO(001) Bare NiO(001) Spin reorientation at the antiferromagnetic NiO(001) surface in response to an adjacent ferromagnet H. Ohldag, A. Scholl, F. Nolting, S. Anders, F.U. Hillebrecht, and J. Stöhr Exchange bias Unidirectional anisotropy in FM adjacent to AFM discovered 1956 by Meiklejohn and Bean Exchange-bias field (size depends on many parameters) The exchange bias effect is exploited in magnetic data storage devices, though the origin of this effect is still poorly understood. Different models do exist, most of them assume that the magnetic structure at the surface is the same as for the bulk. Interfacial spins Spin-flop PEEM Meiklejohn, Bean (1956) Takano et al. (1997) Koon (1997) • High Spatial Resolution • Elemental Sensitivity • Ferromagnetic Contrast • Antiferromagnetic Contrast • Surface/Interface Sensitivity FM AFM step grain / domain boundary

More Related