Surface structure of Gd-5(Si,Ge)(4) crystals

Crystal growth of Gd5Si4, Gd5Si2Ge2 and Gd5Ge4 was performed using the Czoc hralski method from the levitated melt. Single crystalline plates were obta ined for all compounds. The Berg-Barrett topography revealed the existence of stress within the plates. The surface of the plates shows a regular syst em of lines or channels, which is independent of the growth steps and the s tress structure. The auger electron spectroscopy investigation of that stru cture revealed the increase of gadolinium and oxygen contents in the area o f lines, which had the width of about 2 mu m. We suppose this concentration of impurities may take place along dislocations, which could be formed dur ing the structural transition at high temperature. (C) 1999 Elsevier Scienc e B.V, All rights reserved.