W. M. Keck Imaging Facility

Through a generous grant from the W. M. Keck Foundation, we have recently acquired a state-of-the-art facility for electron microscopy. The facility consists of two transmission electron microscopes (TEMs), a new JEOL 2010F ultra-high resolution field emission TEM, and a refurbished JEOL 2000FX analytical TEM.

The JEOL FasTEM 2010F provides lattice imaging with a point resolution of 0.19 nm and an extended information limit near 0.10 nm. This instrument has many peripheral devices to enhance analysis, including scanning capability (STEM) with high-angle annular dark field detection, energy loss spectroscopy and imaging, and energy dispersive X-ray spectroscopy. In addition, this instrument is internet-ready, allowing for collaborative access and remote control of the instrument.

The JEOL 2000FX is used as a general purpose TEM and as a teaching instrument. It has a point resolution of 0.29 nm and is equipped with STEM capability and energy dispersive X-ray spectroscopy.

These instruments are equipped with a variety of specimen holders, allowing studies at temperatures from 20 K to 1270 K, cryogenic transfer studies, and studies with very low X-ray background.

This facility also houses two scanning electron microscopes, a JEOL 840 SEM and a Philips PSEM 501.

High resolution image of the [110] projection in La2NiO4.058 taken on the JEOL 2010F FasTEM. The image was captured digitally using a Gatan Imaging Filter Multi-Scan Camera at 810K Magnification. The white box in the lower left-hand corner indicates the [110] projection of the 3.8 Å x 12.6 Å unit cell with space group I 4/m m m.

The structure of La2NiO4 in [110] projection. The NiO2 layers shown in pink and orange correspond to the rows of faint spots. The La2O2 layer shown in pink and blue correspond to the double rows of bright spots. The unit cell is I 4/mmm with a ~ 3.8 Å and c ~ 12.6 Å