Loops and Spirals on Thermally Etched Surfaces of Cleaved NaCl Crystals

摘要: Freshly cleaved (100) surfaces of laboratory grown single crystals NaCl were thermally etched by placing them in a muffle furnace on platinum lid. In addition to the usual square etch pits, various closed loop patterns have been beautifully illustrated. It is conjectured that circular patterns, having central spiral, might formed as explained Lang (1957), while pattern similar originating at Frank-Read sources and multiple pairs dislocations opposite nature.