The growth of single crystal samples of Bi-2212, large enough for x-ray measurements of the kind intended here, can be achieved in several ways. The earliest, and probably still most common means is to grow crystals from the melt. Because of the incongruent melting of the compound, a solvent is required, and the primary means has been to use the self flux formed during a directional growth process. The traveling solvent floating zone (TSFZ) method is a more recent technique applied to Bi-2212 and which has a number of advantages over the crucible growth methods.
Each of the four crystals used in these measurements was grown
independently by a different research group; The institute of
Physics, Beijing, University of Birmingham, University of Oxford,
and University of Warwick. And each crystal will be referred to by
its place of origin. Crystals grown by both Beijing (as
described by Yan [102]) and Birmingham were grown by
the flux method in alumina crucibles. The Oxford crystal was grown
in a platinum crucible [103]. The Warwick crystal
was grown using the Traveling Solvent Floating Zone (TSFZ)
process [104]. All the crystals were
carefully selected from batches of samples by initial microscopic
examination for large flat shiny surfaces and their true crystalline
nature was then checked by preliminary x-ray diffraction. Many
apparently single crystal samples under detailed examination were
often found to have a multi-crystalline nature, being composed
of many single crystal grains all of which have their axes slightly
misaligned by only a degree or two, and are thus unsuitable for
these measurements. The four crystals so selected were
of varying dimensions, roughly ranging from 
2 x 1 x 0.02 mm
up to 5 x 3 x 0.02 mm, and all with the characteristic platelet
shape with the c axis as face normal. The longest face
dimension was consistently found to correspond to the a axis.