Pseudo-Hall effect and anisotropic magnetoresistance in a micronscale Ni80Fe20 device

The pseudo-Hall effect (PHE) and anisotropic magnetoresistance (AMR) in a micronscale Ni80Fe20, six-terminal device, fabricated by optical lithography and wet chemical etching from a high quality UHV grown 30 Angstrom Au/300 Angstrom Ni80Fe20 film, have been studied. The magnetisation reversal in different parts of the device has been measured using magneto-optical Kerr effect (MOKE), The device gives a 50% change in PHE voltage with an ultrahigh sensitivity of 7.3%Oe(-1) at room temperature. The correlation between the magnetisation, magneto-transport properties, lateral shape of the device and directions of the external applied field is discussed based on extensive MOKE, AMR and PHE results

Influence of lateral geometry on magnetoresistance and magnetisation reversal in Ni80Fe20 wires

The magnetisation reversal processes and magnetoresistance behaviour in micron-sized Ni80Fe20 wires with triangular and rectangular modulated width have been studied. The wires were fabricated by electron beam lithography and a lift-off process. A combination of magnetic force microscopy (MFM), magneto-optical Kerr effect (MOKE) and magnetoresistance (MR) measurements shows that the lateral geometry of the wires greatly influences the magnetic and transport properties. The width modulations modify not only the shape-dependent demagnetising fields, but also the current density. The correlation between the lateral geometry, the magnetic and the transport properties is discussed based on MFM, MOKE and MR results

Magnetization reversal and magnetic anisotropy in Co network nanostructures

The magnetization reversal and magnetic anisotropy in Co network structures have been studied using magneto-optic Kerr effect (MOKE). An enhancement of the coercivity is observed in the network structures and is attributed to the pinning of domain walls by the hole edges in the vicinity of which the demagnetizing field spatially varies. We find that the magnetization reversal process is dominated by the intrinsic unaxial anisotropy (2K(u)/M(s)approximate to 200 Oe) in spite of the shape anisotropy induced by the hole edges. The influence of the cross-junction on the competition between the intrinsic uniaxial anisotropy and the induced shape anisotropy is discussed using micromagnetic simulations

Investigation of silicon isolated double quantum-dot energy levels for quantum computation

The fabrication methods and low-temperature electron transport measurements are presented for circuits consisting of a single-island single-electron transistor coupled to an isolated double quantum-dot. Capacitively coupled ‘trench isolated’ circuit elements are fabricated in highly doped silicon-on-insulator using electron beam lithography and reactive ion etching. Polarisation of the isolated double quantum-dot is observed as a function of the side gate potentials through changes in the conductance characteristics of the single-electron transistor. Microwave signals are coupled into the device for excitation of the polarisation states of the isolated double quantum-dot. Resonances attributed to an energy level splitting of the polarisation states are observed with an energy separation appropriate for quantum computation

Investigation of silicon isolated double quantum-dot energy levels for quantum computation

The fabrication methods and low-temperature electron transport measurements are presented for circuits consisting of a single-island single-electron transistor coupled to an isolated double quantum-dot. Capacitively coupled ‘trench isolated’ circuit elements are fabricated in highly doped silicon-on-insulator using electron beam lithography and reactive ion etching. Polarisation of the isolated double quantum-dot is observed as a function of the side gate potentials through changes in the conductance characteristics of the single-electron transistor. Microwave signals are coupled into the device for excitation of the polarisation states of the isolated double quantum-dot. Resonances attributed to an energy level splitting of the polarisation states are observed with an energy separation appropriate for quantum computation

THE ANNEALING BEHAVIOUR OF HIGH DOSE As+ IMPLANTS

Le recuit de doses aussi importantes que 4.1016 ions/cm2, implantées à l'aide de courants allant jusqu'à 10mA, est décrit. Les différences entre le recuit isothermique rapide et le recuit au four, introduites sur la mesure de la résistance des feuilles, sont dues aux quantités différentes de diffusion et à la diminution d'arsenic du fait de l'évaporation. La qualité du matériau n'est pas affectée par l'intensité des forts cornants (10mA) utilisés tant que l'élévation de la température, pendant l'implantation, reste faible.The annealing behaviour of doses up to 4.1016 ions/cm2 implanted at ion currents up to 10mA is described. Differences between rapid isothermal and furnace annealing in the measured sheet resistances are due to different amounts of diffusion and to loss of dopant by evaporation. Implantation at high currents (10mA) does not appear to affect the quality of the regrown material provided the temperature rise during implantation is small