We review results obtained from recent neutron scattering studies of the lead-oxide class of perovskite relaxors PMN and PZN. A ferroelectric soft mode has been identified in PMN at 1100 K that becomes overdamped near 620 K. This is the same temperature at which polar nanoregions (PNR) begin to form, denoted by Td , and suggests that a direct connection exists between the soft mode and the PNR....

The mechanisms that drive metal-to-insulator transitions (MIT) in correlated solids are not fully understood, though intricate couplings of charge, spin, orbital, and lattice degrees freedom have been implicated. For example, the perovskite SrCoO3 is a ferromagnetic metal, while oxygen-deficient (n-doped) brownmillerite SrCoO2.5 an antiferromagnetic insulator. Given magnetic structural accompan...

Protonic conductors of BaZr0.5Ce0.3Ln0.2O3-δ (BZCLn532, Ln=Y, Sm, Gd, Dy) were successfully synthesized by using a cost-effective solid state reactive sintering (SSRS) method with 1 wt.% NiO as a sintering aid. The pellets of the BZCLn532 were obtained at sintering temperatures between 1300 1600 °C. The results show that the morphologies and the final relative densities of the obtained BZCLn532...

The perovskite compounds ABO3 are one of the most common oxide structures and thus have been extensively studied. Indeed, they present a very large panel of interesting physical properties (ferroelectricity, piezoelectricity, superconductivity ...) [1]. Some of them also present magnetic properties and are thus potentially multiferroic. Multiferroic materials are widely investigated nowadays, b...

Automotive exhaust is one of the main generators of air pollutants. This problem is expected to worsen as the demand for privately owned vehicles increases. Internal combustion engines utilizing gasoline and diesel generate harmful pollutants such as nitrogen oxides (NOx), carbon monoxide (CO), unburned hydrocarbons (HC), particulates, and sulfur oxides (SOx). Liquefied petroleum gas (LPG), an ...

Complex oxide materials are a mixture of metal and oxygen ions that exhibit a wide variety of physical functionalities1. They are among the most abundant minerals on Earth, and are of interest in many commercial technologies, from displays to electronics and communication to sensors and actuators. The multifunctional nature of these materials has opened up many possibilities for fundamental res...

Piezoelectrics are key functional materials in actuator and sensor applications. Current technology exploits lead-based materials displaying a morphotropic phase boundary (MPB) between two ferroelectric solid solutions of different symmetries and polarization directions. This is best exemplified by the PbZr1 xTixO3 (PZT) perovskite system where the distortions driving the piezo response are pro...

Because of the technological importance of perovskite-based oxides, numerous pathways towards new structures have been developed, including ordering at the A and/or B cation sites of the perovskite (ABO3) structure, vacancy ordering at the anion site, the intergrowth of perovskite and related structures, and the formation of hexagonal perovskite polytypes. However, it has been generally accepte...

The structural and electrical properties of CaMnO3 prepared by a sol-gel technique using citric acid as a chelating agent at 8000C were studied; the phase formation was determined by powderXRD. The surface morphological studies were carried out through SEM and EDX confirmed the chemical compositions of the sample. The various modes of vibrations due to the Mn-O and O-Mn-O stretching bonds were ...