1. Magnetron sputtering chamber
We have designed an original UHV chamber (400 mm diameter) allowing the deposition of metallic thin layers of controlled thickness (angstrom resolution) and multi-layers. Possibility of making binding layers (layers of attachment) as well as layers of protection is granted. Three sources are confocal thus opening the possibility to obtain alloys of controlled stochiometry.
Characteristics:
- base pressure : 1x10-8 mbar (turbo pump + cryo pump).
- number of sources: at present four 1 inch sources and two sources of 2 inches size are available, out of a maximum of eleven possible slots.
- available source targets (1 inch) : Si, Ti, Py, Mg, Pt, Gd, Pd, Rh, Ti, Mo, Fe, Sm, Al, Cr, Cu, Co, Ni, Au, Ta, graphite, Ir.
- quality of the plasma composition during deposition is monitored by the use of a residual gas analyzer.
- rotation of the substrate (1-10 Hz).
- heating of the substrate up to 500 K, polarisation is possible.
- the transfer of the substrate is facilitated by a fast load-lock, a garage being also available.
- home-made control and versatile LabView program.
2. MOKE setup
In order to characterise the magnetisation of solid samples whe have developped a modern magneto-optical Kerr effect (MOKE) setup using a Wollaston prism and a lock-in amplifier.
Two geometries are available: polar MOKE to measure the perpendicular component of the magnetization and longitudinal MOKE to determine the in-plane component (faded in the picture).
3. UHV MOKE setup
We are currently developping a new MOKE setup to achieve 2 T under ultra-high vacuum (5x10-10 mbar) conditions. A conventional electromagnet is used, the poles of the magnet are under vacuum but not the coils; we are therefore not limited by thermal issues and it is possible to apply up to 100 A. Three quartz viewing ports arranged at 60° to each other allow to measure both polar and longitudinal Kerr signals. The transition from one geometry to the other is done by simple rotation of the sample. The pre-alignment of the optical benches that are situated outside vacuum allows us to switch from polar and longitudinal within few minutes. The system is equipped with a cryostat, a temperature range from 150 K and 450 K being available.
It is therefore possible to measure the evolution with temperature of the hysteresis curves and determine the Curie temperature of the samples.
Contact : R. Delaunay