T Irisawa et al 2009 New J. Phys. 11 113031 doi:10.1088/1367-2630/11/11/113031
T Irisawa1, T K Yamada1,2,3 and T Mizoguchi1
Show affiliationsThe atomic and electronic structures at the apex of W tips were studied by means of field ion microscopy and field emission microscopy, before and after the thermal deposition of a 5 nm Fe film. Two geometries of W tip, a conventional hemi-spherical type and a chisel (flat needle) type, were prepared. The hemispherical and the chisel W tips had a
110
direction parallel and perpendicular to the tip axis, respectively. The coated Fe films were found to be most likely in a non-crystalline phase, and to have a lower work function leading to a drastic change in electron emission from the apexes. The spin-polarization vectors of field-emitted electrons from these Fe/W tips were investigated with a Mott detector with a rotatable mechanism of tips. A similar absolute value of the spin-polarization vector
was obtained for each Fe/W, while the direction of the spin-polarization vector was dependent on the shape of the apex. The angle from the tip axis was θ=45° for the hemispherical apex and θ=66° for the chisel apex. A spin-polarized scanning tunneling microscopy setup with a rotation mechanism of such Fe/W tips made it possible to detect both the in-plane and the out-of-plane spin component of a sample magnetization.
72.25.Mk Spin transport through interfaces
73.20.At Surface states, band structure, electron density of states
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
Issue 11 (November 2009)
Received 8 July 2009
Published 17 November 2009
T Irisawa et al 2009 New J. Phys. 11 113031
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