Title :
Magnetoresistance of FeCo Nanocontacts With Current-Perpendicular-to-Plane Spin-Valve Structure
Author :
Fuke, Hiromi Niu ; Hashimoto, Susumu ; Takagishi, Masayuki ; Iwasaki, Hitoshi ; Kawasaki, Shohei ; Miyake, Kousaku ; Sahashi, Masashi
Author_Institution :
Corporate Res. & Dev. Center, Toshiba Corp., Kawasaki
fDate :
6/1/2007 12:00:00 AM
Abstract :
We have achieved a magnetoresistance (MR) ratio of 7%-10% at a resistance area product (RA) of 0.5-1.5 Omegamum2 by ferromagnetic FeCo nanocontacts in Al nano-oxide-layer (NOL) with current-perpendicular-to-plane spin-valve (CPP-SV) structure. Conductive atomic-force-microscopy shows clear current-path regions of a few nanometers in size surrounded by the Al-NOL. The MR dependence on resistance area product (RA) is well explained by the current-confined-path model assuming that the spin-dependent scattering has an FeCo nanocontact origin, different from tunnel magnetoresistance (TMR). Resistance increases with increasing bias voltage, indicating joule heating by high-current density in nanocontacts, in contrast to TMR. The MR origin is mainly interpreted as spin-dependent scattering due to domain wall formed at ferromagnetic nanocontact
Keywords :
atomic force microscopy; cobalt alloys; ferromagnetic materials; iron alloys; magnetic domain walls; nanocontacts; spin valves; tunnelling magnetoresistance; AlO; FeCo; TMR; conductive atomic-force-microscopy; current-perpendicular-to-plane spin-valve structure; domain wall; ferromagnetic nanocontacts; nanooxide-layer; spin-dependent scattering; tunnel magnetoresistance; Ballistic magnetoresistance; Giant magnetoresistance; Iron; Magnetic devices; Magnetic domain walls; Magnetic domains; Magnetic recording; Nanocontacts; Scattering; Tunneling magnetoresistance; Conductive atomic-force-microscopy; domain wall; nanocontact magnetoresistance (MR); spin-valve;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2007.893117
