HIGH-TEMPERATURE CRYSTALLINE EFFECTS IN AUGER-ELECTRON SPECTROSCOPY -THE POSSIBILITY OF OBSERVATION OF THE SURFACE ROUGHENING TRANSITION ON THE NI(110) FACE

The Auger signal of the M2,3VV (62 eV) transition is measured as a fun ction of the primary beam incidence angle for the (001) and (110) nick el faces with the samples maintained at temperatures of 300-1500 K Fro m those measurements the contrast C = 2(I(max) - I(min))/(I(max) + I(m in)) is calculated for the direction normal to the surface and the dep endence of In C on the sample temperature is presented. For the Ni(001 ) face two linear parts of this dependence are found in the whole temp erature range used (with the smaller and larger slope below and above 740 K, respectively) while for the Ni(110) face In C drops appreciably faster than linearly for T > 1300 K. The increased slope above 740 K observed for both samples is ascribed to the anharmonic effects, while the fast drop of In C observed for the Ni(110) face for T > 1300 K is interpreted as a result of thermal roughening of this face. Thus, cry stalline effects in AES can give information on the thermal roughening .