2018-Sustainable Industrial Processing Summit
SIPS2018 Volume 4. Mamalis Intl. Symp. / Advanced Manufacturing
| Editors: | F. Kongoli, A. G. Mamalis, K. Hokamoto |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2018 |
| Pages: | 352 pages |
| ISBN: | 978-1-987820-88-1 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Transition Metal Oxides: A Vast Investigative Field for Functional Materials
Bernard Raveau1;1UNIVERSITY OF CAEN, Normandy, France;
Type of Paper: Plenary
Id Paper: 156
Topic: 48
Abstract:
Transition metal oxides have been the object of numerous investigations by solid state chemists and physicists since the pioneering work on oxygen tungsten bronzes by Hägg and Magnéli in the 1950a's. Due to the diversity of their structural frameworks and of the d-electron interactions of the transition elements, very attractive physical properties were observed for oxides. Their high stability at different temperatures and in various atmospheres and the possibility to fabricate them either in the form of dense polycrystalline ceramics, or of single crystals, but also of thin films and as nanoparticles, make that the properties of these materials can be easily tailored and optimized by doping with various elements in view of specific applications. Curiously, the realization of oxide-based functional materials has been rather limited until 1986, date of the discovery of high critical temperature (Tc) superconductivity in cuprates. We discuss herein the role of several classes of transition metal oxides in the realization of functional materials.
From the numerous high Tc cuprates that were discovered during the rush to superconductivity, YBCO and BiSCCO superconductors which exhibit a zero resistance below 90 K/ 110 K , are now used as functional materials. The latter allow high magnetic fields to be produced without any overheating and consequently are used for medical purpose (magnetic resonance imaging of the brain), but also in high current transportation cables, current leads and accelerator electromagnets. Electronic applications of these cuprates have also been realized, as for example electrical motors, SQUID detectors based on Josephson junctions (earth, submarine, brain) and microprocessors for ultra-rapid computers. The Meissner effect of these oxides makes that they are used in magnetic levitation as for example in Maglev trains and magnetic bearings.
Cobaltates represent a very important class that is investigated for producing and saving energy in transportation. This is the case of lithium-based cobaltates that are used as electrode materials in lithium ion batteries. and of bismuth/alkaline earth "misfit" cobaltates which exhibit good thermoelectric performances at high temperature in air (high thermoelectric power, low resistivity and low thermal conductivity) allowing to save energy by conversion of waste heat into electricity. Similarly, cobaltates and manganates with an ordered oxygen deficient perovskite structure exhibit an exceptionally high oxygen mobility and consequently are attractive materials for solid oxide fuel cell (SOFC's) applications.
Metal oxides containing Mn/Fe/Co have also been investigated for their potential in the field of memory devices and quantum computation. This is exemplified by numerous studies of colossal magnetoresistance (CMR) manganates. Recently, oxides called multiferroics, with complex properties, combining ferroelectricity and ferromagnetism have been discovered, with gigantic variation of polarization suggesting possible applications in this field.