Contrast of Kikuchi Bands above and below the Critical Voltage

• Published in: Journal of the Physical Society of Japan Vol. 34; no. 5; pp. 1297 - 1302
• Main Author: Arii, Tatsuo
• Format: Journal Article
• Language: English
• Published: Tokyo The Physical Society of Japan 01-01-1973
• ISSN: 0031-9015; 1347-4073
• DOI: 10.1143/JPSJ.34.1297

Electron diffraction patterns including the 111 systematic Kikuchi bands from relatively thin (\lesssim2000 Å) nickel crystals are taken at symmetric incidence below (100 and 195 kV) and above (335, 385 and 470 kV) the critical voltage for the 222 reflection, Ec=295 kV. As is usually observed, all bands except the 222 band are defect near the incident spot and excess far from it at any accelerating voltage, E. On the other hand, the 222 band is excess very near the \bar1\bar1\bar1 and 111 reflection spots, defect in the intermediate region and again excess far from the incident spot for E<Ec. For E>Ec, its contrast reverses in the first and second regions and becomes hardly observable in the third region. The observed behaviour of contrast is interpreted by considering the many-beam effect and the crystal structure factor for Kikuchi pattern.