J. Ayache - Academia.edu (original) (raw)

Papers by J. Ayache

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... minimum of artifacts. Given the very small size of the sample to be analyzed in the TEM, the ... more ... minimum of artifacts. Given the very small size of the sample to be analyzed in the TEM, the initial material will often need to be reduced using preliminary preparation techniques: sawing, cutting, dimpling, cleavage, etc. In order ...

Revue de Physique Appliquée

Materials Science Forum

We have combined TEM (Transmission Electron Microscopy), HREM (High Resolution Electron Microscop... more We have combined TEM (Transmission Electron Microscopy), HREM (High Resolution Electron Microscopy) and AFM (Atomic Force Microscope) techniques to study growth induced defects in YBCO thin film bicrystals. AFM images clearly evidence "in-plane waviness" of the grain boundary (GB) and a quantitative analysis of HREM images shows unambiguously the oscillation of the grain boundary plane, This GB structure and morphology results from the island growth mechanism of the film.

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... Techniques involved: sawing, mechanical polishing, dimpling, crushing, ultra-microtomy, cryo-... more ... Techniques involved: sawing, mechanical polishing, dimpling, crushing, ultra-microtomy, cryo-ultramicrotomy, freeze fracture, and extractive replica. ... Techniques involved: sawing, mechanical polishing, dimpling, tripod polishing, ultramicrotomy, and cryo-ultramicrotomy. ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... (FeS 2 ), granite, silicate HgS, corundum, diamond Metal ∑ Mercury, lead, PbSb T in, gold, al... more ... (FeS 2 ), granite, silicate HgS, corundum, diamond Metal ∑ Mercury, lead, PbSb T in, gold, aluminum, silv er, copper, magnesium, cadmium, bronze Iron, nick el, platinum, carbon steel, stainless steel T itanium, chrome, tantalum, allo y steel Zirconium, Cemented steel ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... occur. 2.2.1 Techniques Involving Cutting by Means of Mechanical Abrasion: Sawing and Grindin... more ... occur. 2.2.1 Techniques Involving Cutting by Means of Mechanical Abrasion: Sawing and Grinding Cutting ... parts. This is the case for sawing, cutting with a cutting tool, ultrasonic grinding, and electrical-discharge machining (EDM). The ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

Page 1. Chapter 4 Mechanical Preparation Techniques 1 Crushing 1.1 Principle Crushing is used to ... more Page 1. Chapter 4 Mechanical Preparation Techniques 1 Crushing 1.1 Principle Crushing is used to very quickly produce a fine powder from a bulk material or fine particle using mechanical crushing. This technique is essentially ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... 1.2.2 Procedure The 3-mm disk is cut using either a precision die (cuts without deformation) ... more ... 1.2.2 Procedure The 3-mm disk is cut using either a precision die (cuts without deformation) or by EDM in a slice with parallel faces, obtained by sawing or mechanical polishing. ... In the case of bulk materials, the foil is obtained by sawing and/or mechanical polishing. ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

Page 1. Chapter 2 Preliminary Preparation Techniques 1 Sawing 1.1 Principle ... In most cases, th... more Page 1. Chapter 2 Preliminary Preparation Techniques 1 Sawing 1.1 Principle ... In most cases, this means obtaining a slice with parallel faces of the right thickness (a foil or disk 1-to 0.1-mm thick). The sawing technique uses the mechanical effect of abrasion. ...

... Conception et réalisation de la couverture : Perez Dan © Publications de l'Université de... more ... Conception et réalisation de la couverture : Perez Dan © Publications de l'Université de Saint-Étienne, 2007 35 rue du Onze Novembre 42023 Saint-Étienne Page 5. ... Elles concernent principa-lement l'étude des matériaux biologiques et polymères. ...

Superconducting and Related Oxides: Physics and Nanoengineering III, 1998

ABSTRACT Josephson tunnel junctions between a conventional superconductor (Pb) and a High Tc mate... more ABSTRACT Josephson tunnel junctions between a conventional superconductor (Pb) and a High Tc material YBa2Cu3O7-(delta ) (YBCO) have been reproducibly obtained in a film based planar geometry. Using a quasi-MBE method to grow high quality thin films, and making in-situ Pb/YBCO junctions along different crystallographic orientations, we studied the Josephson coupling along the (001) and (103) directions, together with the excitation spectra through quasi-particle tunneling. We evidenced that the coupling along the c- direction is small but finite, compatible with a small s-wave component in YBCO, and that a Zero Bias Conductance Peak is present when tunneling in the ab-plane, as expected for an Andreev Bound State (ABS) at a surface of a dominantly d-wave superconductor. The role of twin boundaries in c-axis experiments is discussed, and the coupling between the ABS with the Josephson current as well.

Physica C, 1994

ICentre de Recherche stir la Physique des Hautes Temp6ratures, CNR.S 45071 Orl6ans cedex 2, Franc... more ICentre de Recherche stir la Physique des Hautes Temp6ratures, CNR.S 45071 Orl6ans cedex 2, France. 2Laboratoire de Physiqne des Mat6riaux, CNRS, lpl Aristide Briand, 92 195 Meudon cedex, France. 3Laboratoire

Materials Science Forum, 1993

Page 1. Materials Science Forum Vol. 116 (1993) pp 149-168 © (1993) Trans Tech Publications, Swit... more Page 1. Materials Science Forum Vol. 116 (1993) pp 149-168 © (1993) Trans Tech Publications, Switzerland doi: 10.4028/www. scientific. net/MSF. 116.149 Materials Science forum vol. iio(ivv3/pp. /4y-/oe Copyright Trans Tech ...

Superconductor Science and Technology, 1992

Microstructure and microchemistry characterizations have been made using analytical transmission ... more Microstructure and microchemistry characterizations have been made using analytical transmission electron microscopy in order to correlate extended defect formation to intergranular and intragranular current density values. AC magnetization curves as a function of applied magnetic field at 4.2 and 77 K have been obtained. The results show that a large density of twins favours a high intragranular critical current density. In addition, the formation of cationic non-stoichiometric phases can act as vortex pinning centres. The relatively high intergranular current density is in good agreement with the observed absence of intergranular grain boundary phases.

Superconductor Science and Technology, 1994

Microstructures of textured YBa2Cu3O7-x ceramics were examined by transmission electron microscop... more Microstructures of textured YBa2Cu3O7-x ceramics were examined by transmission electron microscopy. The samples were synthesized under a residual thermal gradient by using modified melt textured growth on a Y oxide substrate. Defects running parallel to stacking (ab) planes are in fact growth defects associated with 211 trapped particles. Microanalysis of such areas proves the presence of solidified liquid in these

Physica C: Superconductivity, 1995

ABSTRACT Residual carbon content in powders, sintered ceramics and textured samples was determine... more ABSTRACT Residual carbon content in powders, sintered ceramics and textured samples was determined. Its source was shown to be essentialy the starting material precursors. Carbon content may be reduced to below 600 ppm if no liquid phase is formed during precursor processing. The case of samples processed by solidification from a liquid is important. In samples textured on MgO substrate, carbon is supplied by this substrate. In this case, liquid phase plays an active role on the carbon retention in the YBa2Cu3O7−x structure during crystallisation. Magnetic susceptibility behaviour of textured samples was analysed and discussed in relation to the presence of carbon. A qualitative correlation between the superconducting transition width and the carbon content was established. A sharp superconducting transition at 91.5 K was achieved when carbon content was less than 600 ppm.

Physica C: Superconductivity, 1994

A zone melting set-up with a magnetic field perpendicular to the temperature gradient is used in ... more A zone melting set-up with a magnetic field perpendicular to the temperature gradient is used in order to optimize (a, b) plane alignment and thus critical current densities. Large samples with high Jc values in magnetic fields at 77K are obtained. These studies are carried out by optical microscopy, analytical transmission electron microscopy and X ray diffraction pole figures. Our results indicate that crystallite misorientation within a single domain does not exceed 10% The application of a magnetic field of 5 T imposes the c-axis orientation during grain growth. Indeed, we observe an intergrain dispersion much smaller than 40 ° with respect to the magnetic field direction. The 123 matrix contains large amounts of unoriented 211 inclusions which are of different size.

Physica C: Superconductivity, 1994

We have studied by analytical TEM and HREM the microstructure and the nanostructure of 123 matrix... more We have studied by analytical TEM and HREM the microstructure and the nanostructure of 123 matrix/211 inclusion interfaces in order to determine their cristallographic relationship and their chemistry. Three types of relaxed interfaces have been characterized called A1, A2., and A3.These are related to interracial extended defect formation and to texttration mechanism.

Physica C: Superconductivity, 1990

ABSTRACT We have studied the hysteresis loops of three YBa2Cu3O7-x ceramics characterized by diff... more ABSTRACT We have studied the hysteresis loops of three YBa2Cu3O7-x ceramics characterized by different grain sizes (2, 7 and 10 mum). The measurements are based on 16 bits analog to digital conversion, the applied magnetic field being alternating at a frequency of 20 Hz and with a maximum amplitude of 300 Oe. We observed that the irreversible phenomena (area of the loops) largely increase when reducing the grain size. Considering that the measured magnetization can be separated into two terms characteristics of the inter- and intragranular regions, we suggest that at 4.2 K and for H

Materials Science and Engineering: B, 1998

Copper deficiency is studied in YBa 2 Cu 3 O 7 − x phase. We compare polycrystals formed by sinte... more Copper deficiency is studied in YBa 2 Cu 3 O 7 − x phase. We compare polycrystals formed by sintering with textured and single crystals. The experimental method uses electron probe micro-analysis and X-ray structural determinations on single crystals. We show that YBa 2 Cu 3 O 7 − x phase accommodates Cu deficiency up to several percent. Copper vacancies are located at the Cu(1) site (in the chains). Copper deficiency is evidenced when a liquid phase is involved in the chemical process. The implications of copper vacancies on the physical properties has probably to be reconsidered in future.

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... minimum of artifacts. Given the very small size of the sample to be analyzed in the TEM, the ... more ... minimum of artifacts. Given the very small size of the sample to be analyzed in the TEM, the initial material will often need to be reduced using preliminary preparation techniques: sawing, cutting, dimpling, cleavage, etc. In order ...

Revue de Physique Appliquée

Materials Science Forum

We have combined TEM (Transmission Electron Microscopy), HREM (High Resolution Electron Microscop... more We have combined TEM (Transmission Electron Microscopy), HREM (High Resolution Electron Microscopy) and AFM (Atomic Force Microscope) techniques to study growth induced defects in YBCO thin film bicrystals. AFM images clearly evidence "in-plane waviness" of the grain boundary (GB) and a quantitative analysis of HREM images shows unambiguously the oscillation of the grain boundary plane, This GB structure and morphology results from the island growth mechanism of the film.

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... Techniques involved: sawing, mechanical polishing, dimpling, crushing, ultra-microtomy, cryo-... more ... Techniques involved: sawing, mechanical polishing, dimpling, crushing, ultra-microtomy, cryo-ultramicrotomy, freeze fracture, and extractive replica. ... Techniques involved: sawing, mechanical polishing, dimpling, tripod polishing, ultramicrotomy, and cryo-ultramicrotomy. ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... (FeS 2 ), granite, silicate HgS, corundum, diamond Metal ∑ Mercury, lead, PbSb T in, gold, al... more ... (FeS 2 ), granite, silicate HgS, corundum, diamond Metal ∑ Mercury, lead, PbSb T in, gold, aluminum, silv er, copper, magnesium, cadmium, bronze Iron, nick el, platinum, carbon steel, stainless steel T itanium, chrome, tantalum, allo y steel Zirconium, Cemented steel ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... occur. 2.2.1 Techniques Involving Cutting by Means of Mechanical Abrasion: Sawing and Grindin... more ... occur. 2.2.1 Techniques Involving Cutting by Means of Mechanical Abrasion: Sawing and Grinding Cutting ... parts. This is the case for sawing, cutting with a cutting tool, ultrasonic grinding, and electrical-discharge machining (EDM). The ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

Page 1. Chapter 4 Mechanical Preparation Techniques 1 Crushing 1.1 Principle Crushing is used to ... more Page 1. Chapter 4 Mechanical Preparation Techniques 1 Crushing 1.1 Principle Crushing is used to very quickly produce a fine powder from a bulk material or fine particle using mechanical crushing. This technique is essentially ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

... 1.2.2 Procedure The 3-mm disk is cut using either a precision die (cuts without deformation) ... more ... 1.2.2 Procedure The 3-mm disk is cut using either a precision die (cuts without deformation) or by EDM in a slice with parallel faces, obtained by sawing or mechanical polishing. ... In the case of bulk materials, the foil is obtained by sawing and/or mechanical polishing. ...

Sample Preparation Handbook for Transmission Electron Microscopy, 2010

Page 1. Chapter 2 Preliminary Preparation Techniques 1 Sawing 1.1 Principle ... In most cases, th... more Page 1. Chapter 2 Preliminary Preparation Techniques 1 Sawing 1.1 Principle ... In most cases, this means obtaining a slice with parallel faces of the right thickness (a foil or disk 1-to 0.1-mm thick). The sawing technique uses the mechanical effect of abrasion. ...

... Conception et réalisation de la couverture : Perez Dan © Publications de l'Université de... more ... Conception et réalisation de la couverture : Perez Dan © Publications de l'Université de Saint-Étienne, 2007 35 rue du Onze Novembre 42023 Saint-Étienne Page 5. ... Elles concernent principa-lement l'étude des matériaux biologiques et polymères. ...

Superconducting and Related Oxides: Physics and Nanoengineering III, 1998

ABSTRACT Josephson tunnel junctions between a conventional superconductor (Pb) and a High Tc mate... more ABSTRACT Josephson tunnel junctions between a conventional superconductor (Pb) and a High Tc material YBa2Cu3O7-(delta ) (YBCO) have been reproducibly obtained in a film based planar geometry. Using a quasi-MBE method to grow high quality thin films, and making in-situ Pb/YBCO junctions along different crystallographic orientations, we studied the Josephson coupling along the (001) and (103) directions, together with the excitation spectra through quasi-particle tunneling. We evidenced that the coupling along the c- direction is small but finite, compatible with a small s-wave component in YBCO, and that a Zero Bias Conductance Peak is present when tunneling in the ab-plane, as expected for an Andreev Bound State (ABS) at a surface of a dominantly d-wave superconductor. The role of twin boundaries in c-axis experiments is discussed, and the coupling between the ABS with the Josephson current as well.

Physica C, 1994

ICentre de Recherche stir la Physique des Hautes Temp6ratures, CNR.S 45071 Orl6ans cedex 2, Franc... more ICentre de Recherche stir la Physique des Hautes Temp6ratures, CNR.S 45071 Orl6ans cedex 2, France. 2Laboratoire de Physiqne des Mat6riaux, CNRS, lpl Aristide Briand, 92 195 Meudon cedex, France. 3Laboratoire

Materials Science Forum, 1993

Page 1. Materials Science Forum Vol. 116 (1993) pp 149-168 © (1993) Trans Tech Publications, Swit... more Page 1. Materials Science Forum Vol. 116 (1993) pp 149-168 © (1993) Trans Tech Publications, Switzerland doi: 10.4028/www. scientific. net/MSF. 116.149 Materials Science forum vol. iio(ivv3/pp. /4y-/oe Copyright Trans Tech ...

Superconductor Science and Technology, 1992

Microstructure and microchemistry characterizations have been made using analytical transmission ... more Microstructure and microchemistry characterizations have been made using analytical transmission electron microscopy in order to correlate extended defect formation to intergranular and intragranular current density values. AC magnetization curves as a function of applied magnetic field at 4.2 and 77 K have been obtained. The results show that a large density of twins favours a high intragranular critical current density. In addition, the formation of cationic non-stoichiometric phases can act as vortex pinning centres. The relatively high intergranular current density is in good agreement with the observed absence of intergranular grain boundary phases.

Superconductor Science and Technology, 1994

Microstructures of textured YBa2Cu3O7-x ceramics were examined by transmission electron microscop... more Microstructures of textured YBa2Cu3O7-x ceramics were examined by transmission electron microscopy. The samples were synthesized under a residual thermal gradient by using modified melt textured growth on a Y oxide substrate. Defects running parallel to stacking (ab) planes are in fact growth defects associated with 211 trapped particles. Microanalysis of such areas proves the presence of solidified liquid in these

Physica C: Superconductivity, 1995

ABSTRACT Residual carbon content in powders, sintered ceramics and textured samples was determine... more ABSTRACT Residual carbon content in powders, sintered ceramics and textured samples was determined. Its source was shown to be essentialy the starting material precursors. Carbon content may be reduced to below 600 ppm if no liquid phase is formed during precursor processing. The case of samples processed by solidification from a liquid is important. In samples textured on MgO substrate, carbon is supplied by this substrate. In this case, liquid phase plays an active role on the carbon retention in the YBa2Cu3O7−x structure during crystallisation. Magnetic susceptibility behaviour of textured samples was analysed and discussed in relation to the presence of carbon. A qualitative correlation between the superconducting transition width and the carbon content was established. A sharp superconducting transition at 91.5 K was achieved when carbon content was less than 600 ppm.

Physica C: Superconductivity, 1994

A zone melting set-up with a magnetic field perpendicular to the temperature gradient is used in ... more A zone melting set-up with a magnetic field perpendicular to the temperature gradient is used in order to optimize (a, b) plane alignment and thus critical current densities. Large samples with high Jc values in magnetic fields at 77K are obtained. These studies are carried out by optical microscopy, analytical transmission electron microscopy and X ray diffraction pole figures. Our results indicate that crystallite misorientation within a single domain does not exceed 10% The application of a magnetic field of 5 T imposes the c-axis orientation during grain growth. Indeed, we observe an intergrain dispersion much smaller than 40 ° with respect to the magnetic field direction. The 123 matrix contains large amounts of unoriented 211 inclusions which are of different size.

Physica C: Superconductivity, 1994

We have studied by analytical TEM and HREM the microstructure and the nanostructure of 123 matrix... more We have studied by analytical TEM and HREM the microstructure and the nanostructure of 123 matrix/211 inclusion interfaces in order to determine their cristallographic relationship and their chemistry. Three types of relaxed interfaces have been characterized called A1, A2., and A3.These are related to interracial extended defect formation and to texttration mechanism.

Physica C: Superconductivity, 1990

ABSTRACT We have studied the hysteresis loops of three YBa2Cu3O7-x ceramics characterized by diff... more ABSTRACT We have studied the hysteresis loops of three YBa2Cu3O7-x ceramics characterized by different grain sizes (2, 7 and 10 mum). The measurements are based on 16 bits analog to digital conversion, the applied magnetic field being alternating at a frequency of 20 Hz and with a maximum amplitude of 300 Oe. We observed that the irreversible phenomena (area of the loops) largely increase when reducing the grain size. Considering that the measured magnetization can be separated into two terms characteristics of the inter- and intragranular regions, we suggest that at 4.2 K and for H

Materials Science and Engineering: B, 1998

Copper deficiency is studied in YBa 2 Cu 3 O 7 − x phase. We compare polycrystals formed by sinte... more Copper deficiency is studied in YBa 2 Cu 3 O 7 − x phase. We compare polycrystals formed by sintering with textured and single crystals. The experimental method uses electron probe micro-analysis and X-ray structural determinations on single crystals. We show that YBa 2 Cu 3 O 7 − x phase accommodates Cu deficiency up to several percent. Copper vacancies are located at the Cu(1) site (in the chains). Copper deficiency is evidenced when a liquid phase is involved in the chemical process. The implications of copper vacancies on the physical properties has probably to be reconsidered in future.