Electric-field-induced orthorhombic phase in Pb[(Zn1∕3Nb2∕3)0.955Ti0.045]O3 single crystals

The ferroelectric phase transitions of [1¯01]-, [001]-, and [111]-oriented Pb[Zn1∕3Nb2∕3]O3–4.5%PbTiO3 (PZN–4.5%PT) single crystals were investigated as a function of temperature (T between 300 and 450K), and electric field (E field between 0 and 300kV∕m) by dielectric and x-ray diffraction combined measurements. Under null E field, PZN–4.5%PT exhibits the following phase transitions: cubic (C)→tetragonal (T)→rhombohedral (R), during cooling. Under E field applied on a [1¯01]-oriented single crystal, an intermediate orthorhombic (O) ferroelectric phase is induced at temperatures intermediate between that of the T and R phases. The temperature range of existence of this O phase depends both on the crystal orientation and on the measurement conditions: field cooling (FC), zero-field heating after field cooling (ZFHAFC), or field heating (FH). When E field is applied along [1¯01], the stability range is within 40K in FC and only 15K in ZFHAFC; when E field is applied along [001] or [111], this range is still...