Selecting optimal R6TX2 intermetallics (R = Gd, Tb, Dy; T = Mn, Fe, Co, Ni; X = Sb, Te) for magnetic refrigeration.
A Herrero1, I R Aseguinolaza1, A Oleaga1
1Departamento de Física Aplicada, Escuela de Ingeniería de Bilbao, Universidad del País Vasco UPV/EHU, Plaza Torres Quevedo 1, 48013 Bilbao, Spain. aritz.herrero@ehu.eus.
Dalton Transactions (Cambridge, England : 2003)
|April 11, 2023
Summary
Researchers studied Fe2P-type intermetallic compounds for magnetic refrigeration. These materials exhibit two magnetic transitions, creating a plateau for efficient cooling and high refrigerant capacity, making them promising for advanced magnetic refrigerators.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Thermodynamics
Background:
- Magnetic refrigeration offers an energy-efficient alternative to conventional cooling technologies.
- Fe2P-type intermetallic compounds are candidates for room-temperature magnetic refrigeration due to their magnetic properties.
- Understanding the interplay of structural, magnetic, and thermal properties is crucial for optimizing these materials.
Purpose of the Study:
- To conduct a comprehensive experimental investigation of physical properties relevant to magnetic refrigeration in selected Fe2P-type compounds.
- To evaluate the magnetocaloric effect (MCE) and refrigerant capacity (RC) of these materials near room temperature.
- To analyze the critical behavior of the magnetic phase transitions and their impact on MCE scaling.
Main Methods:
- Experimental synthesis and characterization of nine Fe2P-type R6TX2 intermetallic compounds.
- Measurement of structural, magnetic, magnetocaloric (magnetic entropy change, ΔS_M), and thermal properties (thermal diffusivity, conductivity, specific heat).
- Analysis of magnetic phase transitions (paramagnetic-ferromagnetic and spin reorientation) and critical phenomena.
Main Results:
- Two distinct magnetic phase transitions were observed: a paramagnetic-ferromagnetic transition (182–282 K) and a spin reorientation (26–76 K).
- The dual transitions generate a table-like plateau in magnetic entropy change, enhancing efficiency for Ericsson cycle refrigerators.
- Tb2Dy4FeSb2 exhibited the highest magnetic entropy change (7.72 J kg−1 K−1 at 182 K for 5 T) and refrigerant capacity (1103.04 J kg−1).
Conclusions:
- The studied Fe2P-type compounds demonstrate significant potential for room-temperature magnetic refrigeration applications.
- The observed dual magnetic transitions and resulting MCE profile are beneficial for high-efficiency cooling.
- Critical exponent analysis reveals complex magnetic interactions, necessitating careful consideration for accurate RC scaling.
Related Concept Videos
01:28Types Of Superconductors
1.1K
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
1.1K
03:02Colors and Magnetism
12.0K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.0K