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Electron Transport across Oxide Interfaces on the Nanoscale
Published in Tamalika Banerjee, Oxide Spintronics, 2019
Kumari Gaurav Rana, Saurabh Roy, Tamalika Banerjee
Complex oxide heterointerfaces are of immense interest in oxide electronics. Creating, engineering and characterizing such functional interfaces have been propelled by the evolution of sophisticated thin film techniques allowing the growth of atomically flat, lattice matched interfaces and probing them for their structures and electronic properties. As a result, many unique transport phenomena have been observed in devices with polar/non-polar interfaces, where the electronic properties are promoted by the presence of an electric field. In this context, although devices with non-polar oxide interfaces have been studied [52–57], little focus has been given to the study of emerging functional properties at their heterointerfaces. The functional interface of metallic SRO with an oxide semiconductor (Nb:STO) Schottky interface provides an excellent template to study this.
Problems of Electron Structure of Colossal Magnetoresistors
Published in Natalia V. Chezhina, Dmitry A. Korolev, Electronic Structure of Materials, 2019
Anna V. Fedorova, Natalia V. Chezhina
Complex oxides with perovskite structure have been studied since the middle of the 20th century.1, 2 In spite of the fact that the first results on electrical properties of lanthanum manganites had been published more than 60 years ago,3 the interest to them did not diminish and reached its peak when the effect of colossal magnetoresistance (CMR) was found in the oxide ceramics based on lanthanum manganite.4 Of the greatest interest are complex oxides with the composition La1−xAxMnO3 (A = Ca, Sr, Ba). The concentration of dopants (x) may vary within wide limits, the properties of ceramic samples varying substantially in doing so, which is associated with various phase transitions and types of ordering.
Powder Synthesis by Chemical Methods
Published in Mohamed N. Rahaman, Ceramic Processing, 2017
Complex oxides are oxides such as titanates, ferrites, and aluminates that contain more than one type of metal in the chemical formula. Earlier, we outlined the drawbacks of the solid-state reaction route for the production of fine, stoichiometric, high-purity powders. Some of those difficulties can be alleviated by the use of coprecipitation from a solution of mixed alkoxides, mixed salts, or a combination of salts and alkoxides. A common problem in coprecipitation is that the different reactants in the solution often have different hydrolysis rates, resulting in segregation of the precipitated material. Suitable conditions must therefore be found to achieve homogeneous precipitation. As an example, consider the preparation of MgAl2O4 powders [34]. Both Mg and Al are precipitated as hydroxides, but the conditions for their precipitation are quite different. Al(OH)3 is precipitated under slightly acidic or basic conditions (pH = 6.5–7.5), is soluble in the presence of excess ammonia, but is only slightly soluble in the presence of NH4Cl. Mg(OH)2 is completely precipitated only in strongly basic solutions such as NaOH solution. In this case, an intimate mixture of Al(OH)3 and Mg–Al double hydroxide, 2Mg(OH)2·Al(OH)3, is produced when a solution of MgCl2 and AlCl3 is added to a stirred excess solution of NH4OH kept at a pH of 9.5–10. Calcination of the precipitated mixture above ~400°C yields stoichiometric MgAl2O4 powder with high purity and fine particle size.
Temperature-dependent model for ferroelectrics embedded into two-dimensional polygonal finite element framework
Published in Mechanics of Advanced Materials and Structures, 2023
Dheeraj Kailas Valecha, Jayabal K, Amirtham Rajagopal
Complex oxides, particularly perovskite oxides, have a wide range of applications. Nonvolatile random-access memories (NVRAMs), Piezoelectric and pyroelectric sensors, surface acoustic wave (SAW) devices, IR detectors (using pyroelectricity), microactuators and applications that require nonlinear optical components, as well as voltage tunable capacitors, can all benefit from ferroelectric properties. Modern applications demand that ferroelastic characteristics be exploited in layered templates containing a ferrimagnetic material and a piezoelectric material like PZT. By applying an electric field throughout the piezoelectric material, this would enable control of the ferrimagnetic material’s magnetic properties. Ferromagnetic materials can serve a variety of purposes in microwave passive components if their internal magnetic fields are strong enough. They also have the potential to maintain voltage tenability, which reduces size [50].
Electronic properties and surface reactivity of SrO-terminated SrTiO3 and SrO-terminated iron-doped SrTiO3
Published in Science and Technology of Advanced Materials, 2018
Aleksandar Staykov, Helena Tellez, John Druce, Ji Wu, Tatsumi Ishihara, John Kilner
Complex oxide, ceramic materials have attracted significant academic and industrial attention recently with their application in the fields of electronics [1], catalysis, photochemistry [2,3], water electrolysis [4], and solid oxide fuel cells (SOFC). Amongst the various crystal lattices of complex oxides, the perovskites play significant role in modern energy relegated materials’ research. They find application in processes like artificial photosynthesis, steam electrolysis, and most importantly, as SOFC electrodes and electrolytes. The perovskite oxide lattice has the general formula ABO3 and it is composed by two different metal ions occupying lattice sites denoted as A-site and B-site. The B-site ions are usually small transition metals characterized with large formal charge, positioned in an octahedral site, coordinated by six oxide ions. Those octahedra are constructing the BO2-sublattice of the perovskites. The A-site ions are usually large alkali and alkaline earth metals occupying the cavities formed by the BO2-sublattice and neutralizing the charge of the material. However, recent development in the perovskite materials often utilizes rare earth elements from the lanthanoid series as A-site cations in perovskite lattices. Those perovskite materials, containing rare earth elements at the A-sites, are often characterized with supreme catalytic activity [5].