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Effective Debye Temperature of the (110) Ni Face for Different Azimuths
Author(s) -
Mróz S.,
Mróz A.,
Grudniewski A.,
Bąk E.
Publication year - 1983
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221170230
Subject(s) - azimuth , debye , debye model , scattering , electron , beam (structure) , anharmonicity , atomic physics , physics , chemistry , materials science , optics , condensed matter physics , quantum mechanics
The effective Debye temperature θ eff for directions normal to the (110) Ni face and with an angle of about 54° to the normal is measured by LEED for different azimuths, for electron energies of 70 to 100 and 130 to 160 eV, respectively, and for the incidence angle of a primary beam of about 60°. Under such conditions the primary electron beam is diffracted mainly on the first layer of atoms and averaging over an azimuth angle should eliminate the multiple scattering effects. Therefore, the averaged effective Debye temperature θ should describe the vibrations of atoms in the first layer. Values of θ⟂ = (218 ± 20) K and θ 54° = (287 ± 20) K are obtained. A dependence of θ eff,54° on the azimuth angle is not found, in contradiction to the theoretical prediction for the face investigated. The ratio 〈 u 2 ⟂〉 / 〈 u bulk 2 〉 calculated by applying our results is equal to 3.37 −0.55 +0.71 , in good agreement with calculations based on quasi‐harmonic and anharmonic approximations.