Chrystals

We supply most metals and several oxides from stock. We also carry several of the more frequently used alloys in stock like Au-Cu and Ni-Al. For current availability and more exotic materials, please place your inquiry through our email, crystals@spl.eu.

In general, the bigger the diameter of a crystal rod that is used to cut a crystal, the higher the number of defects in that rod. Smaller sizes are almost always better and should be preferred when crystallinity is essential for your experiment. To verify available crystal rod dimensions for a specific material, please check the element info pull-down box in the top-right portion of this page.

The standard tolerance of all dimensions on our crystals is +/- 0.1 mm. The two potential exceptions to this are the outer diameter and the total thickness of the crystal and reasons may vary from lack of availability of a suitable diameter source rod of sufficient quality (e.g. cutting a 8x8 mm square shape from a 10 mm diameter rod leads to rounded corners) and details of the polishing process (tighter alignment tolerances mean we have to make more corrections to the orientation of the surface normal in later stages of the polishing process which can compromise the total thickness of the crystal at the expense of an accurate alignment).

Yes, customized crystals are our specialty and we do them all the time. The crystal shapes that are displayed on the Request Quote page are just a limited set of standard shapes of the many crystals that we make on a daily basis. We provide many tailor-made crystals with arbitrary shapes and dimensions, so please send a simple drawing to crystals@spl.eu to verify whether or not the specific design that you have in mind can be made.

The best alignment option that we can offer is to align a crystal surface to an accuracy of approximately 0.1 degrees using our Laue CCD system. From an instrumental point of view a more accurate alignment is theoretically possible, but is pointless since it intertwines with the sampled area of the X-ray beam, the quality of the source rod being used, and the roughness specification of the polished surface. We offer reduced pricing for the alignment if the allowable miscut is less than half a degree or less than one degree.

We are frequently asked to guarantee the width of the specular reflection of a crystal, in particular for demanding applications like X-ray standing waves (XSW). The answer to this question is that we cannot guarantee an exact number and can only offer the smallest possible width on a best-effort basis. To begin with, all crystals that exhibit any appreciable form of mosaicity in our Laue system are tossed out of production. Second, the width of specular or surface reflections is in no small part affected by the polishing procedure. The polishing that we perform on crystalline metal surfaces always leaves a distorted cold work layer that needs to be annealed prior to achieving the ultimate crystallinity. This ultimate crystallinity, which is ideally identical to the quality of the source rod, is only achieved in-situ at the end-user facility and is therefore beyond our control. Third, the equipment that we use to align crystals lacks the possibility to evaluate the quality of a single crystal at the same level of detail that is possible in e.g. modern third generation synchrotrons. Hence we can only commit to providing the best crystallinity on a best-effort basis, but are more than willing to tailor our preparation and polishing procedures towards your experiments, if so requested.

Yes, we can. In fact, our repolishing services include an assessment of the quality of the crystal that you have sent back for repolishing. If the crystallinity is still sufficient to warrant a proper alignment we will provide you the repolished crystal back for just the polishing costs and with no addditional costs for a new crystal. If the crystal lattice is damaged beyond the point where it is stilll deemed to be useful for your experiments, we will contact you to plot a further course of action.

Yes, most definitely so. A metal surface cannot be prepared into an atomicaly flat state through the polishing and etching recipes that we employ to prepare crystals. The polished surfaces that we provide are a starting point for further in-situ preparation in a UHV environment.   The roughness of the polished surface is minimized to provide a surface profile that will naturally evolve into the flattest possible crystal facet of the desired orientation after further sputtering and annealing.

Yes and no. On the one hand: Yes, they are provided in the cleanest possible state on a macroscopic scale and go through several cycles of rinsing in aceton p.A. prior to being shipped out to our customers. On the other hand: No, with the sensitivity  of a surface science technique like LEED or XPS, after our in-house cleaning treatment and transport through ambient, there will always be several monolayers of hydrocarbons and water present on the samples that will prevent the recording of a well-defined LEED pattern or a representative XPS spectrum. Further in-situ preparation will always be required.

At present we offer a single roughness specification for all crystals that we provide. We guarantee an R_a value smaller than 0.03 μm for the full width of the polished surface region. This means that we not only guarantee the flatness on the length scale of atomic terraces, but over the full macroscopic width of the sample to ensure that the orientational accuracy of the surface normal is maintained in a manner that is independent of position.