Giant rotating magnetocaloric effect induced by highly texturing in polycrystalline DyNiSi compound (original) (raw)

Texture-induced enhancement of the magnetocaloric response in melt-spun DyNi2 ribbons

Applied Physics Letters, 2013

The magnetocaloric properties of melt-spun ribbons of the Laves phase DyNi2 have been investigated. The as-quenched ribbons crystallize in a single-phase MgCu2-type crystal structure (C15; space group ) exhibiting a saturation magnetization and Curie temperature of M S = 157 ± 2 A m2 kg−1 and T C = 21.5 ± 1 K, respectively. For a magnetic field change of 2 T, ribbons show a maximum value of the isothermal magnetic entropy change |ΔS M peak| = 13.5 J kg−1 K−1, and a refrigerant capacity RC = 209 J kg−1. Both values are superior to those found for bulk polycrystalline DyNi2 alloys (25% and 49%, respectively). In particular, the RC is comparable or larger than that reported for other potential magnetic refrigerants operating at low temperatures, making DyNi2 ribbons promising materials for use in low-temperature magnetic refrigeration applications. F d 3 ¯ m

Use of Magnetocaloric Material for Magnetic Refrigeration System: A Review

Material Science Research India, 2019

Our daily need to cooling system is grown up. The used cooling systems are the source of the harmful changes in the global climate. And so, we need to search a new alternate cooling systems applying environmentally friendly technology that may help in decreasing the pollutions in our world. The progress in materials science allows to use some materials for cooling purposes. This new class of materials is so called "magnetic refrigerator". The basics of magnetic refrigeration depends on the magneto-caloric properties to reach low temperatures and obtain cooling system. The advantage of magnetic refrigerator (MR); First, the cooling efficiency is higher than conventional vapor refrigerator CVM where its cooling efficiency ~30-60% while the cooling efficiency in CVM ~ 5-10%. Second, MR can be more compactly built. Third, it is safe and an environmentally friendly cooling. In this work, we will highlight on the scientific efforts to find optimum properties to be applied as the...

Magnetocaloric Effect and Magnetic refrigeration: analytic and numeric study

arXiv: Materials Science, 2017

This work aims to present an analytical and numerical study of the magnetocaloric effects (MCE) providing realistic proposals about materials that should be chosen in the design of new refrigerator appliances around the room temperature. Starting from a spin Hamiltonian including the exchange interaction, the single-ion anisotropy and the applied magnetic field terms, we have calculated the partition function at a given temperature and derived a set of relevant physical quantities as magnetization, magnetic entropy and specific heat and analyzed their behavior with atomic parameters as spin, exchange and anisotropy. Using numerical programs that we developed by ourselves, we were able to better elucidate the role of each microscopic parameter in order to reinforce the relative cooling power (RCP) and give rise to optimal performances of the refrigerant compound. This approach could be extended to composite materials underscoring a giant MCE at room temperature. Key-words Magnetic re...

Optimization of the refrigerant capacity in multiphase magnetocaloric materials

Applied Physics Letters, 2011

The refrigerant capacity ͑RC͒ of magnetocaloric materials can be enhanced using multiphase materials or composites, which expand the temperature range over which a significant magnetic entropy change can be obtained. Numerical simulations show that by controlling the parameters of the composite ͑the fraction of the different phases and their Curie temperatures͒ improvements of RC of ϳ83% are possible. The maximum applied field plays a crucial, nonmonotonic, role in the optimization. As a proof of concept, it is shown that the combination of two Fe 88−2x Co x Ni x Zr 7 B 4 Cu 1 alloys produces an enhancement in RC of ϳ37%, making it ϳ92% larger than that of Gd 5 Si 2 Ge 1.9 Fe 0.1 .

Magnetic refrigeration-towards room-temperature applications

… B Condensed Matter, 2003

Modern society relies very much on readily available cooling. Magnetic refrigeration based on the magneto-caloric effect (MCE) has become a promising competitive technology for the conventional gas-compression/expansion technique in use today. Recently, there have been two breakthroughs in magnetic-refrigeration research: one is that American scientists demonstrated the world's first room-temperature, permanent-magnet, magnetic refrigerator; the other one is that we discovered a new class of magnetic refrigerant materials for room-temperature applications. The new materials are manganese-iron-phosphorus-arsenic (MnFe(P,As)) compounds. This new material has important advantages over existing magnetic coolants: it exhibits a huge MCE, which is larger than that of Gd metal; and its operating temperature can be tuned from about 150 to about 335 K by adjusting the P/As ratio. Here we report on further improvement of the materials by increasing the Mn content. The large entropy change is attributed to a fieldinduced first-order phase transition enhancing the effect of the applied magnetic field. Addition of Mn reduces the thermal hysteresis, which is intrinsic to the first-order transition. This implies that already moderate applied magnetic fields of below 2 T may suffice. r 2002 Published by Elsevier Science B.V. Keywords: Magnetic refrigeration; Magneto-caloric effect 0921-4526/03/$ -see front matter r 2002 Published by Elsevier Science B.V. PII: S 0 9 2 1 -4 5 2 6 ( 0 2 ) 0 1 7 6 9 -6

Material requirements for magnetic refrigeration applications

International Journal of Refrigeration-revue Internationale Du Froid, 2018

A primary motivation underlying the research on room-temperature magnetic refrigeration is reaching energy efficiency levels beyond what is achievable with vapor-compression technology. However, the goal of building commercially viable magnetic refrigeration systems with high performance and competitive price has not been achieved yet. One of the obstacles to reach this goal is the inadequate properties of the currently existing magnetocaloric materials. In this article, the needed improvements in the properties of the magnetocaloric materials is investigated. Two existing vapor-compression refrigerators are used as reference for the required performance, and magnetic refrigerators are simulated using a numerical model. Apart from the requirements such as uniformity of transition temperature for each layer, small increment in transition temperature in adjacent layers, and mechanical strength of the materials, the study shows that for the investigated cases materials with adiabatic entropy change 2.35 times larger than the existing materials are needed to outperform vapor-compression systems.

Study of Room Temperature Magnetic Refrigeration

2020

In this paper Thermodynamic performance analysis for a magneto caloric material such as Gadolinium and Terbium is presented. Performance parameter is taken as magnetic entropy change and temperature change at constant room temperature, different magnetic fields. Furthermore the thermodynamic performance is compare between gadolinium and Terbium. Also, a study on the development of magnetic refrigerator at room temperature has been also carried out a model of Rotating Magnetic refrigeration has been developed. By use of MCE it is possible to create magnetic refrigerators—the machines where magnetic materials are used as working bodies instead of a gas, and magnetization/demagnetization is used instead of compression/expansion in conventional refrigerators. To realize any cooling process, it is necessary to have a system in which entropy depends on temperature and some external parameter. In the case of a gas this parameter is pressure, and in the case of a magnetic material it is mag...