Acoustic Emission Study of PZN-7%PT Crystals

Abstract

respectively. It is shown that AE is a very sensitive method for detecting both the PNRs kinetics and low distortion phase transitions in relaxor ferroelectrics.

Electric field dependences of Curie and Néel phase transition temperatures in magnetoelectric relaxor multiferroic Pb(Fe0.5 Ta0.5 )O3 crystals seen via acoustic emission

“…In addition, both T d % 610 K with _ N d % 55 s À1 and T Ã % 500 K with _ N Ã % 70 s À1 were detected here in a good coincidence with many well-known RFEs (inset in Fig. 1) [9,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][30][31][32][33][34][35][36]. So, all the points, characteristic for RFEs, as well as all the phase transitions, characteristic of ferroelectric multiferroics, were successfully detected.…”

“…Uncoupled mobile and non interacting between themselves the PNRs with the sizes of about few unit cells, within the ordered regions [1][2][3][4], appear at high enough Burns temperature, T d , which is located in many well-known perovskite-type RFEs within the temperature range of 440-750 K [9,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Upon cooling, the PNRs growth and at another characteristic temperature, called the intermediate temperature, T Ã , they undergo a structural martensite-like phase transition [31], begin to couple and merge into larger ones [21], become long-lived, static, and their polarization starts [22,32], to interact between themselves, and so the deviation from a Curie-Weiss law or the onset of a frequency dispersion begins [33].…”

Acoustic emission pronounced field‐induced response near critical point in Ba0.6Sr0.4TiO3 ferroelectrics

“…Fluctuating PNRs nucleate at the so‐called Burns temperature ( T d ), which is usually some hundred degrees above the temperature of the T m . In many well‐known Pb‐based RFEs, T d was reliably measured within the temperature range of 600–750 K . Upon cooling, PNRs begin to couple, their flipping dynamics slow down, and at another characteristic temperature, called the intermediate temperature T * , they undergo a structural martensite‐like phase transition, merge into larger ones , become long‐lived and ever static , and so a deviation from a Curie–Weiss law or the onset of a frequency dispersion begins .…”

Relaxor–ferroelectric crossover seen via characteristic temperatures of BaxSr1–xTiO3 ferroelectrics detected by acoustic emission

“…Uncoupled dynamical PNRs appear at high enough Burns temperature (T d ), which is located in many well-known perovskite-type RFEs within the temperature range of 440 Ä 750 K, determined using the dielectric properties and Brillouin light scattering [5][6][7][8][9][10][11][12], polarized Raman spectra [13,14], acoustic emission (AE) [15][16][17][18][19][20][21][22], and thermal expansion [15,16,23,24]. Upon cooling, the PNRs growth and at another characteristic temperature, called the intermediate temperature (T * ), they undergo a structural martensite-like phase transition [25], begin to couple and merge into larger ones [14], become long-lived, static, and their polarization starts [15,26] to interact between themselves, and so the deviation from a Curie-Weiss law or the onset of a frequency dispersion begins [27].…”

“…Upon cooling, the PNRs growth and at another characteristic temperature, called the intermediate temperature (T * ), they undergo a structural martensite-like phase transition [25], begin to couple and merge into larger ones [14], become long-lived, static, and their polarization starts [15,26] to interact between themselves, and so the deviation from a Curie-Weiss law or the onset of a frequency dispersion begins [27]. In perovskite-type RFEs, T * is found to be within the temperature range of 450-570 K, determined using the dielectric properties and Brillouin light scattering [5][6][7][8][9][10][11][12], polarized Raman spectra [13,14,28,29], AE [15,[17][18][19][20][21][22]30], and thermal expansion [15,24]. On further cooling, due to the interaction of PNRs, the giant and smeared frequently dependent temperature maximum of dielectric constant, T m occurs, in which no structural phase transition takes place, i.e., the RFEs remain in paraelectric phase (PE) (canonical RFEs).…”