The Quantum Spin-Polarized Low-Energy Electron Microscope (QSPLEEM) is an Elmitec LEEM III microscope. It is a unique, highly-modifiable low-voltage electron microscope for the study of surfaces and interfaces with a liquid helium sample stage cryostat designed to reach temperatures of ~4 K. The instrument is very sensitive to structural and electronic properties of sample surfaces and is well-suited for in-situ research within a highly controlled sample environment with the ability to vary sample temperature and apply fields and biases. Spin-polarization of the electron beam permits imaging of magnetic domain microstructure.
This instrument is designed to be easily adaptable to enable various types of experiments and exploration of new ideas. During imaging, it is usually possible to provide the following: clean vacuum (low 10-11 torr); variable sample temperature (~ 4 K to over 2500 K); in-situ deposition of films or multilayers (most metals, some oxides), co-deposition of several components. Within limits, magnetic fields at the sample can be adjusted. Samples can be introduced through a loadlock and can be cleaned within the same UHV system (low-energy sputtering with noble- or reactive gases, heating, in-situ cleaving…). Available imaging/spectroscopic modes include bright/dark field low-energy electron microscopy, low-energy electron diffraction, photoemission electron microscopy, angle-resolved reflection electron spectroscopy, and Auger electron spectroscopy.
During imaging, it is usually possible to provide:
- Clean vacuum (low 10-11 torr).
- Variable sample temperature (~4 K to over 2500 K).
- In-situ deposition of film or multilayers (including most metals, some oxides, co-deposition of several components).
- Within limits, magnetic field at the sample can be adjusted.
- Samples can be introduced through a loadlock and can be cleaned within the same UHV system (including low-energy sputtering with noble- or reactive gases, heating, in-situ cleaving).
- Electron energy typically 0 to 100 eV, energy width ~0.1 eV.
- Spin-polarization (normally ~30 %) can be adjusted to point in any polar/azimuthal direction
- Spatial resolution ~10 nm laterally, atomic resolution along surface normal.
- Angular resolution of magnetization direction can be better than 2 deg.
- Time resolution: frame rate can be up to 20 fps, exposure time of several ms per frame is usually required for reasonable signal quality, pump/probe operation remains untested.