Temperature dependence of the Debye-Waller factor for magnesium measured by energy-dispersive diffractometry

The Debye-Waller factor for powdered magnesium was measured in the temperature range 293 to 700 K by the energy-dispersive X-ray method. The results are compared with published theoretical calculations based on the quasi-harmonic and the anharmonic approximations. Anisotropy was found in the behaviour of the temperature factor B(T), with excellent agreement in the a axis direction between the experimental and theoretical calculations within the quasi-harmonic approximation. In the c axis direction, however, the experimental values at increasing temperature exceed the theoretical values, even in the anharmonic approximation.