Download or read book Thin Films Based on Gadolinium Applied to the Magnetic Refrigeration written by Asmaa Endichi and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The search for materials with a giant magnetocaloric effect in a massive state and at a temperature close to ambient temperature is of great interest and is mainly obtained by varying the composition of the materials. However, the first-order transition in these materials exhibits considerable thermal hysteresis, making them difficult to handle in applications for refrigerators operating cyclically. Much effort has been made in recent years to reduce this hysteresis, but the performance obtained with these massive materials does not meet the requirements of efficient magnetic refrigeration. Magnetocaloric materials have been largely unexplored on the nanoscale. However, nanostructuring is a well-known and used approach to disrupt the developed structure-property relationships, hence the interest in manufacturing new nanoscale materials. This will improve their magnetic and magnetocaloric characteristics by varying the size and shape. On the other hand, the magnetocaloric effect in magnetic thin layers is particularly interesting for micro-refrigeration. It is therefore important to study the magnetocaloric properties of materials in the form of thin layers in order to eliminate thermal hysteresis. In this sense, few studies have been done to show the potential of thin film materials for magnetic refrigeration and magnetic properties (saturation magnetization, variation of magnetic entropy and relative cooling ratio ...) measured so far limited remains. In this thesis project, we studied metallic gadolinium, which is the preferred choice as a magnetic refrigerant for most prototypes of active magnetic regenerator (AMR) in the form of a thin layer. The magnetocaloric (MCE) and electrocaloric (ECE) properties of the manufactured gadolinium films (Si / Ta / Gd (100 nm) / Pt (3nm)) are measured, in order to obtain more information on the physics behind the interesting electronic and magnetic properties of this material we demonstrate the magneto-caloric effect of the thin film Gd by measuring the electrical transport of the resistance. Thus, during this thesis, the electrical and especially magnetic behaviors of LaCr2Si2C and multiferroics TbMn2O5 are described using the ab-initio method, in order to broaden our understanding of the electronic, magnetic and therefore magnetocaloric characteristics of these compounds based on rare earth. The development of thin layers for magnetic refrigeration was carried out in the materials science research laboratory with the nanomagnetism and spin electronics team at the Jean Lamour Institute in Nancy and the theoretical calculations are made in the material laboratory condensed and interdisciplinary sciences at the Faculty of Sciences of Rabat.
Download or read book Electronic and magnetic properties of bulk gadolinium and iron thin films written by Albert Ballard Andrews and published by . This book was released on 1992 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetocaloric Effect in Thin Films and Heterostructures written by Christopher Bauer and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goals of this work are the optimization of the magnetocaloric effect in Gadolinium thin film structures. We approach this issue from two directions, that of process optimization and of interface effects. Past results showed Gd2O3 in our Gadolinium thin films, and the presence of such oxide seemed to grow with the temperature at which the film was grown or annealed. Comparison of samples grown without chamber gettering to those that were gettered show differences in their structural and magnetic properties, and we conclude that gettering is an effective step in enhancing the quality of Gd thin film samples. Early work with Gd/W heterostructures showed a diminished magnetization of the interfacial gadolinium, which reduces the magnetocaloric response as magnetic entropy is proportional to m2/3. It is known that Fe interfaces can boost the Gd moments per atom to above that seen in bulk. As such, we fabricated a series of Fe/Gd heterostructures to study the effects on the structural and magnetic properties of Gd thin films. The use of Fe as a base layer shows increased high frequency oscillations in X-ray reflectivity measurements, indicating sharp interfaces between Gd and Fe. The magnetocaloric measurements produce a magnetic entropy curve with a novel tail extending leftward, making this an improved material over Gd for applications around 240K. All the same, vector magnetometry is needed to ensure that such tail is not due to rotations within the plane and is a direction for further study.
Download or read book Magnetocaloric Energy Conversion written by Andrej Kitanovski and published by Springer. This book was released on 2014-12-03 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides the latest research on a new alternative form of technology, the magnetocaloric energy conversion. This area of research concerns magnetic refrigeration and cooling, magnetic heat pumping and magnetic power generation. The book’s systematic approach offers the theoretical basis of magnetocaloric energy conversion and its various sub domains and this is supported with the practical examples. Besides these fundamentals, the book also introduces potential solutions to engineering problems in magnetocalorics and to alternative technologies of solid state energy conversion. The aim of the book is therefore to provide engineers with the most up-to-date information and also to facilitate the understanding, design and construction of future magnetocaloric energy conversion devices. The magnetocaloric energy conversion represents an alternative to compressor based refrigerators and heat pumps. It is a serious alternative to power generation with low enthalpy heat sources. This green technology offers an opportunity to use environmentally friendly solid refrigerants and the potentially high energy efficiency follows the trends of future energy conversion devices. This book is intended for postgraduate students and researchers of refrigeration, heat pumping, power generation alternatives, heat regenerators and advanced heat transfer mechanisms.
Download or read book Extractive Metallurgy of Rare Earths written by Nagaiyar Krishnamurthy and published by CRC Press. This book was released on 2004-12-20 with total page 537 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extractive Metallurgy of Rare Earths compiles information from scattered sources that is often available only to specialists. It provides a complete and usable survey of the rare earth resources, extraction, and production of numerous end products that translates to both laboratory and industrial settings. This book is a source of industry expertis
Download or read book Characterization of the Structural and Magnetic Properties of Gd Thin Films written by Daryl V. Williams and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The standard material by which all materials exhibiting magnetocaloric effect are measured is Gadnolinium. In this work we are attempting to understand how nanostructuring can impact the magnetocaloric effect, to this end we have grown Gd in various thin film structures. The samples made were grown via magnetron sputtering on MgO(100) substrates. Samples of thick Gd (2000 Å) were grown and sandwiched between two layers of Cr or W and annealed at increasing temperatures to study how this can perturb the magnetic and structural properties of the Gd. Another set of samples was grown in which Gd (at various thicknesses) is in a multilayer system with W. Here the purpose is to explore how changing the thickness of the Gd can change its magnetic properties. Using the appropriate Maxwell relation, the magnetic entropy change was observed to increase with increasing annealing temperature. In a 0-4T magnetic field change, the peak entropy was found to go from approximately 1.5 J/kg-K for the unannealed sample to 4.4 J/kg-K when annealed to 600°C. The multilayers were found to all have a Tc near 280 K, in contrast with what is predicted by finite size scaling. This is likely due to pinholes in the W layers allowing the Gd to act as one magnetic material.
Download or read book Metallic Glass Based Nanocomposites written by Sumit Sharma and published by CRC Press. This book was released on 2019-09-23 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallic Glass-Based Nanocomposites: Molecular Dynamics Study of Properties provides readers with an overview of the most commonly used tools for MD simulation of metallic glass composites and provides all the basic steps necessary for simulating any material on Materials Studio. After reading this book, readers will be able to model their own problems on this tool for predicting the properties of metallic glass composites. This book provides an introduction to metallic glasses with definitions and classifications, provides detailed explanations of various types of composites, reinforcements and matrices, and explores the basic mechanisms of reinforcement-MG interaction during mechanical loading. It explains various models for calculating the thermal conductivity of metallic glass composites and provides examples of molecular dynamics simulations. Aimed at students and researchers, this book caters to the needs of those working in the field of molecular dynamics (MD) simulation of metallic glass composites.
Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1994 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical and Magnetic Investigations of Magnesium doped Epitaxial Gadolinium Nitride Thin Films written by Chang-Min Lee and published by . This book was released on 2015 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Nanostructured Materials written by Ahmed A. El Gendy and published by Elsevier. This book was released on 2018-06-29 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Nanostructured Materials: From Lab to Fab presents a complete overview of the translation of nanostructured materials into realistic applications, drawing on the most recent research in the field to discuss the fundamentals, synthesis and characterization of nanomagnetics. A wide spectrum of nanomagnetic applications is included, covering industrial, environmental and biomedical fields, and using chemical, physical and biological methods. Materials such as Fe, Co, CoxC, MnGa, GdSi, ferrite nanoparticles and thin films are highlighted, with their potential applications discussed, such as magnetic refrigeration, energy harvesting, magnetic sensors, hyperthermia, MRI, drug delivery, permanent magnets, and data storage devices. Offering interdisciplinary knowledge on the materials science of nanostructured materials and magnetics, this book will be of interest to researchers in materials science, engineering, physics and chemistry with interest in magnetic nanomaterials, as well as postgraduate students and professionals in industry and government. Provides interdisciplinary knowledge on the materials science of nanostructured materials and magnetics Aids in the understanding of complex fundamentals and synthesis methods for magnetic nanomaterials Includes examples of real applications Shows how laboratory work on magnetic nanoparticles connects to industrial implementation and applications
Download or read book Zero Field Magnetic Properties of Gadolinium Terbium and Samarium written by Emma Daniels Hill and published by . This book was released on 1960 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical and Magnetic Investigations of Magnesium doped Epitaxial Gadolinium Nitride Thin Films written by Chʻang-min Yi and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic and Structural Properties of Co Gd Thin Films written by Ashley Cooper Hopkins and published by . This book was released on 1990 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Faraday Rotation and Some Magnetic Properties of Evaporated Thin Films of Iron Nickel Cobalt and Gadolinium written by Frederick J. McClung (Jr) and published by . This book was released on 1961 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Thin Films written by Ronald F. Soohoo and published by . This book was released on 1988 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Ultrathin Films written by Materials Research Society and published by . This book was released on 1993 with total page 866 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Elastocaloric Cooling Devices Based on Shape Memory Alloy Films written by Brüderlin, Florian and published by KIT Scientific Publishing. This book was released on 2022-11-15 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Elastocaloric cooling is an emerging solid-state cooling technology with the potential to provide environmentally friendly, efficient cooling. The elastocaloric effect in superelastic shape memory alloy films is used to develop advanced cooling devices for small-scale applications. Cascaded and parallelized devices are developed to increase device temperature span and cooling capacity. The concepts are proven experimentally, a maximum temperature span of 27° C is achieved in a cascaded device.
