Aging, rejuvenation and memory effects in re-entrant ferromagnets

We have studied the slow dynamics of the ferromagnetic phases of the re-entrant CdCr_{2x}In_{2-2x}S_4 system for 0.85<x<=1 by means of low frequency ac susceptibility and magnetization measurements. Experimental procedures widely used in the investigation of the out-of-equilibrium dynamics of spin glasses (such as the x=0.85 compound) have been applied to search for aging, rejuvenation and memory effects, and to test their dependence on the disorder introduced by dilution of the magnetic ions. Whereas the rejuvenation effect is found in all studied samples, the memory effect is clearly enhanced for increasing dilutions. The results support a description of aging in both ferromagnetic and re-entrant spin-glass phases in terms of hierarchical reconformations of domain walls pinned by the disorder.Comment: Service de Physique de l'Etat Condense, DRECAM, DSM, CEA Saclay,91191 Gif sur Yvette Cedex, France, 9 pages, including 7 figures, To appear in Eur. Phys. J. B (2002

Le Jeu de la Hache: A Critical edition and dating discussion

Twenty-six years after the first edition and translation by Sydney Anglo in 1991 of the anonymous manuscript Le Jeu de la hache , many elements can still be significantly improved. This paper offers a completely new critical edition of the text, and a major revision of the translation. This article includes a detailed glossary as well as notes to discuss the many ambiguous passages in the original text. Finally, the studies of the language, the vocabulary, the dialect, the writing style and the physical document make it possible to refine the dating of the manuscript to the third quarter of the fifteenth century, between 1460 and 1485, and its origin, probably Flanders or Wallonia in the entourage of the dukes of Burgundy

Spin Anisotropy and Slow Dynamics in Spin Glasses

We report on an extensive study of the influence of spin anisotropy on spin glass aging dynamics. New temperature cycle experiments allow us to compare quantitatively the memory effect in four Heisenberg spin glasses with various degrees of random anisotropy and one Ising spin glass. The sharpness of the memory effect appears to decrease continuously with the spin anisotropy. Besides, the spin glass coherence length is determined by magnetic field change experiments for the first time in the Ising sample. For three representative samples, from Heisenberg to Ising spin glasses, we can consistently account for both sets of experiments (temperature cycle and magnetic field change) using a single expression for the growth of the coherence length with time.Comment: 4 pages and 4 figures - Service de Physique de l'Etat Condense CNRS URA 2464), DSM/DRECAM, CEA Saclay, Franc

Aging phenomena in spin glass and ferromagnetic phases: domain growth and wall dynamics

We compare aging in a disordered ferromagnet and in a spin glass, by studying the different phases of a reentrant system. We have measured the relaxation of the low-frequency ac susceptibility, in both the ferromagnetic and spin-glass phases of a CdCr_{1.9}In_{0.1}S_4 sample. A restart of aging processes when the temperature is lowered (`chaos-like' effect) is observed in both phases. The memory of previous aging at a higher temperature can be retrieved upon re-heating, but in the ferromagnetic phase it can rapidly be erased by the growth of ferromagnetic domains. We interpret the behaviour observed in the ferromagnetic phase in terms of a combination of domain growth and pinned wall reconformations, and suggest that aging in spin glasses is dominated by such wall reconformation processes.Comment: SPEC, CEA Saclay, 91191 Gif sur Yvette Cedex, France, to appear in Europhys. Lett. (2000

La réception de Boccace et de la comédie italienne dans Les Corrivaus de Jean de La Taille

Avec Les Corrivaus, pièce composée vers 1562, publiée en 1573, Jean de La Taille est le premier dramaturge français du xvie siècle à offrir au public une comédie née de la contamination de sources diverses : un récit du Décaméron de Boccace, Les Abusez de Charles Estienne et la comédie I Suppositi de l’Arioste. Cet article examine comment l’héritage facétieux de ces modèles est assumé, transformé et assimilé au goût national, pour aboutir à la création d’un nouveau théâtre comique françaisWith Les Corrivaus, a play that was written around 1562 and published in 1573, Jean de La Taille is the first French playwright in the sixteenth century to offer the public a comedy born from the contamination of a variety of different sources: a tale from Boccaccio’s Decameron, Les Abusez by Charles Estienne, and the comedy I Suppositi by Ariosto. This article examines how the legacy of facetiousness from these models is adopted, transformed, and assimilated by the nation’s taste, resulting in the creation of a new comic French theate

Le facétieux : mise au jour d’un paradigme critique pour l’étude du genre comique

Le bouquet d’articles ici réunis voit dans l’esprit facétieux une clef pour comprendre la genèse et l’évolution du genre de la comédie au xvie siècle ; les rapports entre facétie et comédie sont envisagés sous des angles socio-esthétique (la question des publics), formel (échange de structures et de motifs narratifs), poétique (le travail d’imitation effectué par les auteurs) et pratique (l’importance de la performance orale et physique)The collection of articles brought together here see in facetiousness and practical jokes a key for understanding the genesis and the evolution of the genre of comedy in the sixteenth century; the relationship between practical jokes and facetiousness on one hand and comedy on the other is imagined from a socio-aesthetic perspective (the question of publics), a formal perspective (the exchange of structures and narrative motifs), a poetic perspective (the work of imitation undertaken by authors), and a practical perspective (the importance of oral and physical performance