Bernard Raveau, born in 1940, is a French researcher in

materials science Materials science is an interdisciplinary field of researching and discovering materials. Materials engineering is an engineering field of finding uses for materials in other fields and industries. The intellectual origins of materials sci ...

, professor emeritus at the

University of Caen Normandy The University of Caen Normandy (French: ''Université de Caen Normandie''), also known as Unicaen, is a public university in Caen, France. History The institution was founded in 1432 by John of Lancaster, 1st Duke of Bedford, the first rector ...

, member of the French Academy of sciences.

Biography

He has directed CRISMAT, a joint laboratory of the National Engineering School of Caen (ENSICAEN) of the University of Caen and the

CNRS The French National Centre for Scientific Research (, , CNRS) is the French state research organisation and is the largest fundamental science agency in Europe. In 2016, it employed 31,637 staff, including 11,137 tenured researchers, 13,415 eng ...

. He worked on

cuprate Cuprates are a class of compounds that contain copper (Cu) atom(s) in an anion. They can be broadly categorized into two main types: 1. Inorganic cuprates: These compounds have a general formula of . Some of them are non-stoichiometric. Many ...

s, with the aim of making them electrodes of capacitors resistant to oxidation due to sintering, without

noble metal A noble metal is ordinarily regarded as a metallic chemical element, element that is generally resistant to corrosion and is usually found in nature in its native element, raw form. Gold, platinum, and the other platinum group metals (ruthenium ...

Karl Alexander Müller Karl may refer to: People * Karl (given name), including a list of people and characters with the name * Karl der Große, commonly known in English as Charlemagne * Karl of Austria, last Austrian Emperor * Karl (footballer) (born 1993), Karl Cac ...

and

Johannes Georg Bednorz Johannes Georg Bednorz (; born 16 May 1950) is a German physicist who, together with K. Alex Müller, discovered high-temperature superconductivity in ceramics, for which they shared the 1987 Nobel Prize in Physics. Life and work Bednorz was bor ...

have shown that some of these compounds are superconductors, beginning the aerea of

high temperature superconductors High-temperature superconductivity (high-c or HTS) is superconductivity in materials with a critical temperature (the temperature below which the material behaves as a superconductor) above , the boiling point of liquid nitrogen. They are "high- ...

. They were awarded the Nobel Prize in Physics in 1987, after having reused a "sandwich" of

copper oxide Copper oxide is any of several binary compounds composed of the elements copper and oxygen. Two oxides are well known, Cu2O and CuO, corresponding to the minerals cuprite and tenorite, respectively. Paramelaconite () is less well characterized. ...

sheets designed by Bernard Raveau and his laboratory in Caen.

Scientific work

Bernard Raveau is a specialist in the crystallochemistry of

transition metal In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. The lanthanide and actinid ...

oxides. He has devoted a large part of his research to solid-state chemistry and materials science. Bernard Raveau discovered new tunnel structures and explained non-stop

stoichiometry Stoichiometry () is the relationships between the masses of reactants and Product (chemistry), products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must ...

phenomena. He then focused on the discovery of original structures with new physical or chemical properties, Bernard Raveau discovered new series of cuprates with a layered structure based on

bismuth Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs nat ...

thallium Thallium is a chemical element; it has Symbol (chemistry), symbol Tl and atomic number 81. It is a silvery-white post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Che ...

, or mercury associated with an alkaline earth cation, which are new superconducting materials at high critical temperature. Bernard Raveau showed the

colossal magnetoresistance Colossal magnetoresistance (CMR) is a property of some materials, mostly manganese-based perovskite oxides, that enables them to dramatically change their electrical resistance in the presence of a magnetic field. The magnetoresistance of conventio ...

(CMR) effect in insulating manganites, in small-sized A cation manganites doped with n, and discovered the CMR effect induced by doping

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

sites with different cations such as

cobalt Cobalt is a chemical element; it has Symbol (chemistry), symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. ...

nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...

chromium Chromium is a chemical element; it has Symbol (chemistry), symbol Cr and atomic number 24. It is the first element in Group 6 element, group 6. It is a steely-grey, Luster (mineralogy), lustrous, hard, and brittle transition metal. Chromium ...

strontium Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to ...

ruthenium Ruthenium is a chemical element; it has symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is unreactive to most chem ...

. This work could have developments in information storage processes. Finally, Bernard Raveau has identified

cobaltite Cobaltite is an arsenide and sulfide mineral with the mineral formula Co As S. It is the naming mineral of the cobaltite group of minerals, whose members structurally resemble pyrite (FeS2). History Cobaltite was first described in 1797 by K ...

s with a disjointed structure (misfits) whose remarkable

thermoelectric The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely, when ...

properties are well studied for energy conversion at high temperatures.

Distinctions

He was awarded Chevalier de la

Légion d'honneur The National Order of the Legion of Honour ( ), formerly the Imperial Order of the Legion of Honour (), is the highest and most prestigious French national order of merit, both military and Civil society, civil. Currently consisting of five cl ...

in 2001. He was awarded the title of Fellow of the

Royal Society of Chemistry The Royal Society of Chemistry (RSC) is a learned society and professional association in the United Kingdom with the goal of "advancing the chemistry, chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the ...

on 25 March 2009 for his work in materials science.

Books

* Bernard Raveau, Claude Michel, Maryvonne Hervieu and Daniel Groult, Crystal Chemistry of High-Tc Superconducting Copper Oxides, Springer Verlag, 1991, 331 p. () * Chintamani N.R. Rao and Bernard Raveau, Transition Metal Oxides: Structure, Properties, and Synthesis of Ceramic Oxides, John Wiley & Sons, 1995, 392 p. ()

References

{{DEFAULTSORT:Raveau, Bernard 1941 births 20th-century French chemists Members of the French Academy of Sciences Living people 21st-century French chemists