15 research outputs found
The influence of long-range correlated defects on critical ultrasound propagation in solids
The effect of long-range correlated quenched structural defects on the
critical ultrasound attenuation and sound velocity dispersion is studied for
three-dimensional Ising-like systems. A field-theoretical description of the
dynamic critical effects of ultrasound propagation in solids is performed with
allowance for both fluctuation and relaxation attenuation mechanisms. The
temperature and frequency dependences of the dynamical scaling functions of the
ultrasound critical characteristics are calculated in a two-loop approximation
for different values of the correlation parameter of the Weinrib-Halperin
model with long-range correlated defects. The asymptotic behavior of the
dynamical scaling functions in hydrodynamic and critical regions is separated.
The influence of long-range correlated disorder on the asymptotic behavior of
the critical ultrasonic anomalies is discussed.Comment: 12 RevTeX pages, 3 figure
Effect of structural defects on anomalous ultrasound propagation in solids during second-order phase transitions
The effect of structural defects on the critical ultrasound attenuation and
ultrasound velocity dispersion in Ising-like three-dimensional systems is
studied. A field-theoretical description of the dynamic effects of
acoustic-wave propagation in solids during phase transitions is performed with
allowance for both fluctuation and relaxation attenuation mechanisms. The
temperature and frequency dependences of the scaling functions of the
attenuation coefficient and the ultrasound velocity dispersion are calculated
in a two-loop approximation for pure and structurally disordered systems, and
their asymptotic behavior in hydrodynamic and critical regions is separated. As
compared to a pure system, the presence of structural defects in it is shown to
cause a stronger increase in the sound attenuation coefficient and the sound
velocity dispersion even in the hydrodynamic region as the critical temperature
is reached. As compared to pure analogs, structurally disordered systems should
exhibit stronger temperature and frequency dependences of the acoustic
characteristics in the critical region.Comment: 7 RevTeX pages, 4 figure