Spin-Lattice Relaxation Effects in Critical Sound Propagation

A. Pawlak
1997 Acta Physica Polonica. A  
The nonasymptotic critical properties of sound propagation are studied in compressible Ising system above Τ. In the present paper we analyse a model where in addition to the coupling to two order-parameter fluctuations tle sound mode couples linearly to the fluctuations of spin-energy and lattice-energy densities. Both subsystems exchange energy with the rate determined by the bare spin-lattice relaxation time: The total energy may be conserved or not. The crossover between insulator-like
more » ... nsulator-like behaviour t -2 α a n d m e t a l -l i k e b e h a v i o u r t i t -( z v ± α ) i n u l t r a s o n i c a t t e n u a t i o n i s i n v e s t i g a t e d according to the value of ultrasonic freqnency, the reduced temperature t, bare relaxation times and various coupling constants.
doi:10.12693/aphyspola.92.449 fatcat:qgzxfxduzjaslnmfzbxxf3gqqq