Organic-template-directed nucleation of strontium fluoride and barium fluoride: Epitaxy and strain

In situ synchrotron x-ray diffraction studies show that barium and strontium fluoride grow preferentially oriented at a fatty-acid monolayer template, with the unit cell spacings initially contracted by similar to1.6% (SrF2) to similar to4% (BaF2). In addition to this macroscopic strain, peak width analysis shows the presence of local strain that relaxes as the crystals grow. In contrast, the diffraction pattern from calcium carbonate grown at the same template shows no preferred crystallographic orientation.