A. Conde

Bio: A. Conde is an academic researcher from University of Seville. The author has contributed to research in topics: Curie temperature & Amorphous metal. The author has an hindex of 47, co-authored 363 publications receiving 9959 citations. Previous affiliations of A. Conde include Spanish National Research Council.

Magnetocaloric effect: From materials research to refrigeration devices

Abstract: The magnetocaloric effect and its most straightforward application, magnetic refrigeration, are topics of current interest due to the potential improvement of energy efficiency of cooling and temperature control systems, in combination with other environmental benefits associated to a technology that does not rely on the compression/expansion of harmful gases. This review presents the fundamentals of the effect, the techniques for its measurement with consideration of possible artifacts found in the characterization of the samples, a comprehensive and comparative analysis of different magnetocaloric materials, as well as possible routes to improve their performance. An overview of the different magnetocaloric prototypes found in literature as well as alternative applications of the magnetocaloric effect for fundamental studies of phase transitions are also included.

The Magnetocaloric Effect and Magnetic Refrigeration Near Room Temperature: Materials and Models

Abstract: In the past 20 years, there has been a surge in research on the magnetocaloric response of materials, due mainly to the possibility of applying this effect for magnetic refrigeration close to room temperature. This review is devoted to the main families of materials suitable for this application and to the procedures proposed to predict their response. Apart from the possible technological applications, we also discuss the use of magnetocaloric characterization to gain fundamental insight into the nature of the underlying phase transition.

Field dependence of the magnetocaloric effect in materials with a second order phase transition: A master curve for the magnetic entropy change

Abstract: The field dependence of the magnetic entropy change can be expressed as ΔSM∝Hn For soft magnetic amorphous alloys n=1 well below the Curie temperature (TC), n=2 in the paramagnetic range, and n≈075 for T=TC The first value can be explained with simple arguments, n=2 is a consequence of the Curie-Weiss law, but n(TC) deviates from mean field predictions From the Arrott-Noakes equation of state, a relation between n(TC) and the critical exponents has been obtained, showing remarkable agreement with experimental data (for an example alloy, predicted n=072 versus experimental n=073) A master curve behavior for the temperature dependence of ΔSM measured for different maximum fields is proposed

Scaling laws for the magnetocaloric effect in second order phase transitions: From physics to applications for the characterization of materials

Abstract: The detailed procedure for constructing the recently proposed phenomenological universal curve for the magnetic entropy change is presented, together with the exponents which control the field dependence of the different magnetocaloric-related magnitudes. Practical applications of the universal curve are also outlined: as a simple screening procedure of the performance of materials, as a method for making extrapolations to temperatures or fields not available in the laboratory, for the reduction of the experimental noise, for correcting the influence of non-saturating conditions, or as a way to eliminate the contribution of minority magnetic phases, among others.

A universal curve for the magnetocaloric effect: an analysis based on scaling relations

Abstract: The universal character of the recent experimentally found master curve for the magnetic entropy change, ΔSM, in studies of the magnetocaloric response of materials is analytically justified by using scaling arguments. The validity of the obtained scaling relations is checked against experimental data as well as the mean field and Heisenberg models. The curves are unique for each universality class. It is shown that the universal curve can be practically constructed in two different ways, reducing the number of required parameters with respect to the previous phenomenological derivation. This opens the possibility of an inexpensive screening of the performance of magnetocaloric materials, as it allows extrapolations to magnetic fields or temperatures not available in some laboratories.

Kirk-Othmer Encyclopedia of Chemical Technology数据库介绍及实例

Abstract: 介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。

Exchange bias in nanostructures

Abstract: The phenomenology of exchange bias and related effects in nanostructures is reviewed. The types of systems discussed include: lithographically fabricated ferromagnetic (FM)—antiferromagnetic (AFM) nanostructures, chemically surface modified FM particles, FM particles embedded in an AFM matrix, controlled core–shell particles, nanoparticles with surface effects and coupled AFM–AFM systems. The main applications of exchange biased nanostructures are summarized. Finally, the implications of the nanometer dimensions on some of the existing exchange bias theories are briefly discussed.

Recent developments in stainless steels

Abstract: This article presents an overview of the developments in stainless steels made since the 1990s. Some of the new applications that involve the use of stainless steel are also introduced. A brief introduction to the various classes of stainless steels, their precipitate phases and the status quo of their production around the globe is given first. The advances in a variety of subject areas that have been made recently will then be presented. These recent advances include (1) new findings on the various precipitate phases (the new J phase, new orientation relationships, new phase diagram for the Fe–Cr system, etc.); (2) new suggestions for the prevention/mitigation of the different problems and new methods for their detection/measurement and (3) new techniques for surface/bulk property enhancement (such as laser shot peening, grain boundary engineering and grain refinement). Recent developments in topics like phase prediction, stacking fault energy, superplasticity, metadynamic recrystallisation and the calculation of mechanical properties are introduced, too. In the end of this article, several new applications that involve the use of stainless steels are presented. Some of these are the use of austenitic stainless steels for signature authentication (magnetic recording), the utilisation of the cryogenic magnetic transition of the sigma phase for hot spot detection (the Sigmaplugs), the new Pt-enhanced radiopaque stainless steel (PERSS) coronary stents and stainless steel stents that may be used for magnetic drug targeting. Besides recent developments in conventional stainless steels, those in the high-nitrogen, low-Ni (or Ni-free) varieties are also introduced. These recent developments include new methods for attaining very high nitrogen contents, new guidelines for alloy design, the merits/demerits associated with high nitrogen contents, etc.