Vortex-like state observed in ferromagnetic contacts

• Point-contacts (PC) offer a simple way to create high current densities, 109 A/cm 2and  beyond,  without  substantial  Joule  heating.   We  have  shown  recently  (Nano  Letters,  7(2007) 927) that conductivity of nanosized PCs between a normal and ferromagnetic metalsexhibits bi-stable hysteretic states versus both bias current and external magnetic field – theeffect typical for spin-valve structures.  Here we report that apart from the bi-stable state athird intermediate-resistance state is occasionally observed.  We interpret this state as due toa spin-vortex in the PC, nucleated either by Oersted field of the bias current and/or by thecircular geometry of PC. The observed three-level-states in the PC conductivity testify that theinterface spins are both weakly coupled to the spins in the bulk and have depressed exchangeinteraction within the surface layer.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Nanoteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Nano-technology (hsv//eng)

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

vortex

spin valve

point contact

micromagnetism

spin

magnetic

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)