Magnetocaloric effect in some magnetic materials in alternating magnetic fields up to 22 Hz
| Autor: | V. V. Koledov, L. N. Khanov, Vladimir G. Shavrov, Sergey Taskaev, I. S. Tereshina, A. B. Batdalov, A. M. Aliev |
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| Rok vydání: | 2016 |
| Předmět: |
Phase transition
Materials science Gadolinium Alloy FOS: Physical sciences chemistry.chemical_element 02 engineering and technology engineering.material 01 natural sciences Refrigerant 0103 physical sciences Materials Chemistry Magnetic refrigeration 010302 applied physics Condensed Matter - Materials Science Condensed matter physics Mechanical Engineering Metals and Alloys Materials Science (cond-mat.mtrl-sci) Field frequency 021001 nanoscience & nanotechnology Magnetic field Amplitude chemistry Mechanics of Materials engineering 0210 nano-technology |
| Zdroj: | Journal of Alloys and Compounds. 676:601-605 |
| ISSN: | 0925-8388 |
| Popis: | Direct measurements of the magnetocaloric effect (MCE) in different materials (Gd, Fe48Rh52, Ni43Mn37.9In12.1Co7 and Ni2.07Co0.09Mn0.84Ga) in alternating magnetic fields with frequencies f < 22 Hz and an amplitude deltaH = 6.2 kOe are carried out. The MCE in Gd shows inconsiderable changes with field frequency. Near paramagnetic-ferromagnetic phase transition in Ni43Mn37.9In12.1Co7 Heusler alloy a slight reduction of MCE with frequency is observed. In weak alternating fields in materials with AFM-FM magneto-structural phase transitions (Fe48Rh52, Ni43Mn37.9In12.1Co7) it is not possible to get a structural contribution to overall MCE because of irreversibility of the transitions in these fields. Near magneto-structural phase transitions the MCE in these alloys has only magnetic contribution, and does not show a significant dependence on the magnetic field frequency. In Ni2.07Co0.09Mn0.84Ga Heusler alloy the MCE vanishes at frequencies about 20 Hz. The obtained results show the increase of frequencies of operating cycles is one of the powerful methods to improve the efficiency of magnetic refrigerators in case of Gd as a refrigerant. 12 pages, 5 figures |
| Databáze: | OpenAIRE |
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