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Relaxor ferroelectric single crystals PMNT with the size of φ40 mm×80 mm have been grown by a modified Bridgman method and their ferroelectric and piezoelectric properties have been characterized. The properties varied with the compositions and cut types. On the (001) cut, PMNT76/24 single crystals exhibited a dielectric constant ε of about 3 400, a dielectric loss of tanδ <0.7%, a piezoelectric constant d33 of 980 pC/N, an electromechanical coupling factor kt of 0.55 and Tc of about 110℃. whereas the properties of PMNT67/33 single crystals on (001) cut were betler: e of about 5 300, tan5 <0.6%, d33 up to 3 000 pC/N, kt 0.64, K33 0.93 and Tc of about 150℃. The piezoelectric properties on other cuts such as (110) and (111) were much lower than those on the (001) cut. The rhombohedral PMNT crystals grown by this method showed more excellent piezoelectric properties than those grown by high temperature solution method and higher value of kt than the rhombohedral PZNT single crystals. it has also been
Relaxor ferroelectric single crystals PMNT with the size of φ 40 mm × 80 mm have been grown by a modified Bridgman method and their ferroelectric and piezoelectric properties have been characterized. The properties varied with the compositions and cut types. On the (001) cut, PMNT76 / 24 single crystals a dielectric constant ε of about 3 400, a dielectric loss of tan δ <0.7%, a piezoelectric constant d33 of 980 pC / N, an electromechanical coupling factor kt of 0.55 and Tc of about 110 ° C. of PMNT67 / 33 single crystals on (001) cut were betler: e of about 5 300, tan5 <0.6%, d33 up to 3 000 pC / N, kt 0.64, K33 0.93 and Tc of about 150 ° C. The piezoelectric properties on other cuts such as (110) and (111) were much lower than those on the (001) cut. The rhombohedral PMNT crystals grown by this method showed more excellent piezoelectric properties than those grown by high temperature solution method and higher value of kt than the rhombohedral PZNT single crysta ls. it has also been