arXiv subjects

Sunggi Baik

Publications and source records attributed to Sunggi Baik.

4 recordsLinked to original sources

arXiv2014

Confirmation of the monoclinic Cc space group for the ground state phase of Pb(Zr0.525Ti0.475)O3 (PZT525): A Combined Synchrotron X-Ray and Neutron Powder Diffraction Study

The low temperature antiferrodistortive phase transition in a pseudo-tetragonal composition of PZT with x=0.525 is investigated through a combined synchrotron x-ray and neutron powder diffraction study. It is shown that the superlattice peaks cannot be correctly accounted for in the Rietveld refinement using R3c or R3c+Cm structural models, whereas the Cc space group gives excellent fits to the superlattice peaks as well as to the perovskite peaks. This settles at rest the existing controversies about the structure of the ground state phase of PZT in the MPB region.

cond-mat.mtrl-sci↗

arXiv2008

Origin of high piezoelectric response of Pb(Zr_xTi_1-x)O_3 at the morphotropic phase boundary: Role of elastic instability

Temperature dependent structural changes in a nearly pure monoclinic phase composition (x=0.525) of Pb(Zr_xTi_1-x)O_3 (PZT) have been investigated using Rietveld analysis of high-resolution synchrotron powder x-ray diffraction data and correlated with changes in the dielectric constant and planar electromechanical coupling coefficient. Our results show that the intrinsic piezoelectric response of the tetragonal phase of PZT is higher than that of the monoclinic phase. It is also shown that the high piezoelectric response of PZT may be linked with an anomalous softening of the elastic modulus (1/S_11) of the tetragonal compositions closest to the morphotropic phase boundary.

cond-mat.mtrl-sci↗

arXiv2008

High-resolution synchrotron XRD study of Zr-rich compositions of Pb(Zr_xTi_1-x)O_3 (0.525\leq x \leq 0.60): evidence for the absence of the rhombohedral phase

Results of Rietveld analysis of the synchrotron XRD data on Pb(Zr_xTi_1-x)O_3 (PZT) for 0.525\leqx\leq0.60 are presented to show the absence of rhombohedral phase on the Zr-rich side of the morphotropic phase boundary (MPB). Our results reveal that the structure of PZT is monoclinic in the Cm space group for 0.525\leq x\leq 0.60. The nature of the monoclinic distortion changes from pseudo-tetragonal for 0.525\leqx\leq0.54 to pseudo-rhombohedral for x>0.54.

cond-mat.mtrl-sci↗

arXiv2007

Evidence for monoclinic crystal structure and negative thermal expansion below magnetic transition temperature in Pb(Fe_1/2Nb_1/2)O_3

The existing controversy about the room temperature structure of multiferroic Pb(Fe_1/2Nb_1/2)O_3 is settled using synchrotron powder x-ray diffraction data. Results of Rietveld refinements in the temperature range 300 to 12K reveal that the structure remains monoclinic in the Cm space group down to 12K, but the lattice parameters show anomalies at the magnetic transition temperature (T_N) due to spin lattice coupling. The lattice volume exhibits negative thermal expansion behaviour, with Alpha = - 4.64 x 10^-6 K^-1, below T_N.

cond-mat.mtrl-sci↗