INTERNAL FRICTION ASSOCIATED WITH DOMAIN WALLS AND FERROELASTIC PHASE TRANSITION IN LNPP

Two internal friction peaks (50 - 100kHz) have been measured in LNPP near its transition temperature. The peak at TC=141°C is associated with the ferroelastic transition where the elastic constant C55 vanishes and the peak at a lower temperature is attributed to the motion of domain walls. The variation of domain walls and its relation to Q-1 were obtained by in situ measurements. The mechanisms of the peaks are discussed