The temperature dependence of piezoelectric, pyroelectric, and dielectric properties have been measured for 001 and 111 oriented 0.92Pb Zn1/3Nb2/3 O3–0.08PbTiO3 PZN-8%PT and 0.955Pb Zn1/3Nb2/3 O3–0.045PbTiO3 PZN-4.5%PT single crystals poled by two different poling methods, i.e., room temperature RT poling and poling through field cooling FC . Compared with the RT poling case, some interesting f...

Detailed knowledge of the phase diagram and the nature of the competing magnetic and superconducting phases is imperative for a deeper understanding of the physics of iron-based superconductivity. Magnetism in the iron-based superconductors is usually a stripe-type spin-density-wave, which breaks the tetragonal symmetry of the lattice, and is known to compete strongly with superconductivity. Re...

Oxide compositions of equimolar YO1.5 and TaO2.5 in the Y–Ta–Zr–O system have attractive properties for high-temperature applications, including as thermal barrier coatings. The effect of zirconia concentration, from 0 to 20 mol.% cation, on the tetragonal-to-monoclinic phase transition has been studied using high-temperature X-ray diffraction, Raman spectroscopy and electron microscopy. The tr...

The effects of phosphorus doping on the structural and superconducting phase transitions of BaNi2(As(1-x)P(x))2 were studied. The specific heat, resistivity, and magnetic susceptibility were measured. The results revealed an abrupt increase in the superconducting transition temperature (T(c)) from 0.6 K in the triclinic phase (space group P1¯) with less phosphorus (x≤0.067) to 3.3 K in the tetr...

We determine the relative thermodynamic stability of competing homogeneously and inhomogeneously ordered ferroelectric phases of PbTiO3 using its free-energy landscape, obtained from constrained-polarization moleculardynamics simulations with a first-principles effective Hamiltonian and thermodynamic integration. While we find that the tetragonal structure is thermodynamically most stable at te...

To gain insights into the fundamental and characteristic features of the surface of doped manganites, we constructed a general magnetic phase diagram of La1−xSrxMnO3 (001) surfaces in the plane spanned by x and the bulk tetragonal distortion c/a, from the first-principles calculations. We found that the surfaces are quite different from the bulk in the sense that both the (La, Sr)O and MnO2 ter...

In situ neutron powder diffraction measurements show that the orthorhombic-to-tetragonal phase transition in YBa2Cu307 —,which occurs near 700 C in a pure oxygen atmosphere, is an order-disorder transition in which the disordering of oxygen atoms into a normally vacant site destroys the one-dimensional Cu-0 chains present in the room-temperature orthorhombic structure. For both structures, the ...