Enhanced polarization properties of ferroelectric (Bi_1/2Na_1/2)TiO₃–Ba(Mg_1/3Nb_2/3)O₃ single crystals grown under high-pressure oxygen atmosphere

Abstract

Single crystals of (Bi 1/2 Na 1/2 )TiO 3 Ba(Mg 1/3 Nb 2/3 )O 3 [(1 ¹ x)BNTxBMN] with x = 4% were grown by the flux method (Po 2 = 0.02 MPa) and the high-Po 2 top-seeded solution growth method (Po 2 = 0.9 MPa) and their crystal structures and properties are investigated along the pseudocubic [001] direction. The crystal grown at a higher Po 2 of 0.9 MPa exhibits a well saturated polarization hysteresis, showing that the rhombohedral phase with x = 4% has a spontaneous polarization (P s ) of 48.5¯C/cm 2 (P s parallel to the pseudocubic [111] direction). The superior properties obtained for the crystal (Po 2 = 0.9 MPa) are discussed in terms of domain clamping and depolarization associated with oxygen vacancies.

Composition-driven structural variation in ferrielectric phase of (Bi1/2Na1/2)TiO3-Ba(Mg1/3Nb2/3)O3

“…We can expect that the control over the structural coupling between polarization and rotation distortion enables a novel materials design of polar perovskites with a wide variety of functionalities. The ferrielectric P4bm phase is present also in the solid solution system of rhombohedral BNT and cubic Ba(Mg 1/3 Nb 2/3 )O 3 44) [45][46][47] In our previous reports, a phase boundary between the R3c and P4bm phases exist at around a BMN composition (x) of 4%-5%, and the mixed state of the R3c and P4bm phases is formed at the compositions near the boundary. 46) However, the details of the P4bm structures near the MPB in the BNT-BMN system is still unclear due to the difficulty in obtaining single-phase powders.…”