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Mean-Square Dynamic Displacements and Atomic Scattering Factors of Ions in Aluminum Nitride

  • N. N. Sirota
  • A. I. Olekhnovich
  • N. M. Olekhnovich

Abstract

The absolute values of the squares of the structure amplitudes (F2) were determined for AIN in the temperature range 85–670°K using monochromatic Cu Kα, radiation. These values were used to calculate the mean-square dynamic displacements and the atomic scattering factors of the Al and the N ions. The values of F2 were used also to find the shortest relative distance (u0 /c) between the Al and the N ions along the c axis. This distance was 0.386 ± 0.001, which is different from 0.375 for a perfect structure (c/a= 1.633) and from 0.380 for the case of equal values of all the shortest atomic spacings (c/a = 1.600). The temperature dependences indicated that the mean-square dynamic displacements \((\overline{{{u}^{2}}})\) in AIN were anisotropic. Thus, at room temperature,these displacement were Open image in new window Open image in new window for the Al ion and Open image in new window , Open image in new window for the N ion. The linear expansion coefficient (α) was also anisotropic. In the temperature range 290–670°K, the components of this coefficient were \({{\alpha }_{z}}=(3.0\pm 0.2)\cdot {{10}^{-6}}{{\deg }^{-1}}\) and \({{\alpha }_{xy}}=(3.8\pm 0.2)\cdot {{10}^{-6}}{{\deg }^{-1}}\). The experimental values F exp 2 were extrapolated to absolute zero and compared with the theoretical values F theor 2 It was found that F exp 2 was less than the theoretical value due to the partial redistribution of the valence electrons away from the aluminum toward the nitrogen.

Keywords

Basal Plane Aluminum Nitride Absolute Zero Dynamic Displacement Linear Expansion Coefficient 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Consultants Bureau, New York 1972

Authors and Affiliations

  • N. N. Sirota
  • A. I. Olekhnovich
  • N. M. Olekhnovich

There are no affiliations available

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