PMC HOMEPAGE

GROUPS

Chemistry group Electrochemistry group EPS group Irregularity group

 

MAGNETIC SPIN FILTERS

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People involved

Jacques Peretti, Yves Lassailly, Georges Lampel

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External Collaborators

Margrit Hansbücken (CRMC-N Marseilles),
Oleg Tereshchenko (Novosibirsk, Russie)

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Transmission of low energy spin polarized electrons through suspended Au/Co multilayers exhibit spectacular spin filter effects. In the case of a bilayer structure containing two Co layers of different thickness, and thus different coercive fields, two distinct saturation magnetization configurations are possible, parallel and anti-parallel. Measurements of electron transmission permit a detemination of the volume and surface contributions to the spin filter effect, and at low energies an absolute measure of the electron beam polarization is possible.

We also study the transmission in vacuum of spin polarized electrons through ferromagnetic Schottky barriers formed by the deposition of a thin magnetic film onto either GaAs or silicon. The current measured in the semiconductor shows an asymmetry according to the relative spin polarizations of the incident electron beam and the magnetic thin film (for a 100 % polarization of the incident beam, asymmetries up to 10 % have been measured). This configuration is similar to a spin valve transistor, and constitutes a highly selective fully solid-state spin detector: compact and far more efficient than other state-of-the-art spin detectors such as the Mott polarimeter.

In the near future, this type of spin detector is likely to replace those used today in high energy physics and may open possibilities in spin polarized electron microscopy which to date have been constrained by the incompatibility of conventional spin detection techniques with electron optics.

Selected publications

• "Injection energy dependence of spin-polarized hot-electron transport through a ferromagnetic metal/oxide/semiconductor junction" N. Rougemaille, D. Lamine, G. Lampel, Y. Lassailly and J. Peretti, Phys. Rev. B 77, 094409 (2008)
• "Spin Filtering of Free Electrons by Magnetic Multilayers: Towards an Efficient Self-Calibrated Spin Polarimeter", C. Cacho, Y. Lassailly, H.-J. Drouhin, G. Lampel, and J. Peretti, Phys. Rev. Lett. 88, 066601 (2002)
• "Spin-dependent electron transport in ferromagnetic bilayers: Application to three-dimensional spin detectors"*, N. Rougemaille, H.-J. Drouhin, G. Lampel, J. Peretti, Y. Lassailly, and A. Schuhl, J. Appl. Phys. 91, 8408 (2002)
• "Spin-Dependent Transmission of Electrons through the Ferromagnetic Metal Base of a Hot-Electron Transistorlike System", A. Filipe, H.-J. Drouhin, G. Lampel, Y. Lassailly, J. Nagle, J. Peretti, V. I. Safarov, and A. Schuhl, Phys. Rev. Lett. 80, 2425 (1998)
• "Spin-dependent transmission of free electrons through ultrathin cobalt layers", H.-J. Drouhin, A. J. van der Sluijs, Y. Lassailly, and G. Lampel, J. Appl. Phys. 79, 4734 (1994)
• "Spin-dependent transmission of low-energy electrons through ultrathin magnetic layers", Y. Lassailly, H.-J. Drouhin, A. J. van der Sluijs, G. Lampel, and C. Marlière, Phys. Rev. B 50, 13054 (1994)