Electric-Field Effects on Dielectric Permittivity and Domain Structures of Relaxor-Based Ferroelectric Crystals (PbMg1/3Nb2/3O3)1-x(PbTiO3)x

• Main Authors: Chih-Long Tsai, 蔡志龍
• Other Authors: C.-S. Tu
• Format: Others
• Language: en_US
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/94970103790044748444

碩士 === 輔仁大學 === 物理學系 === 89 === Dielectric Permittivity and domain structures have been measured as a function of temperature in relaxor-based ferroelectric single crystals (PbMg1/3Nb2/3O3)1-x(PbTiO3)x(PMN-x%PT) for x = 0.32 and 0.33 along [001], [110]and[122] orientations, respectively. As temperature increases, PMN-32%PT and PMN-33%PT undergo successive phase transitions: rhombohedral phase ® coexistence of rhombohedral and tetragonal phases ® tetragonal phase ® coexistence of tetragonal and cubic phases ® cubic phase. A relaxation mechanism which is responsible for the so-called diffuse transition, crossovers a wide-temperature region of ~340-400 K, and may result from partial microdomains conversion from rhombohedral to the tetragonal phase. Extra peak dielectric anomalies were observed in each crystal, possibly due to the percolating polar cluster induced by an external electric field. A field-induced tetragonal symmetry was evidenced and coexists with rhombohedral symmetry in the low-temperature region. In addition, field-induce tetragonal phase along the external field was observed.