From direct to inverse giant magnetocaloric effect in Co-doped NiMnGa multifunctional alloys

0358968 - FZÚ 2012 RIV GB eng J - Článek v odborném periodiku
Fabbrici, S. - Kamarád, Jiří - Arnold, Zdeněk - Casoli, F. - Paoluzi, A. - Bolzoni, F. - Cabassi, R. - Solzi, C. - Porcari, G. - Pernechele, C. - Albertini, F.
From direct to inverse giant magnetocaloric effect in Co-doped NiMnGa multifunctional alloys.
Acta Materialia. Roč. 59, č. 1 (2011), s. 412-419. ISSN 1359-6454. E-ISSN 1873-2453
Grant CEP: GA ČR GA202/09/0030
Výzkumný záměr: CEZ:AV0Z10100521
Klíčová slova: Ni–Mn–Ga–Co * ferromagnetic shape memory alloys * magnetostructural transformations * magnetic properties * inverse magnetocaloric effect
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 3.755, rok: 2011
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We report the magnetic and magnetocaloric properties in Co-doped Ni-Mn-Ga Heusler alloys around the Mn-rich composition Ni50Mn30Ga20. The presence of Co affects profoundly the critical temperatures and alters the exchange interactions of martensite and austenite to different extents by varying the composition it is possible to tune the critical temperatures and to induce a paramagnetic gap between the magnetically ordered martensite and magnetic austenite,thus giving rise to a reverse magnetostructural transformation.Contrary to the Co-free alloys,the saturation magnetization moment of austenite is strongly enhanced by Co with respect to the martensitic one:thus the magnetocaloric effect turns from direct into inverse.Remarkable values of the magnetic properties related to the magnetocaloric effect,e.g. the saturation magnetization jump at the transformation(DM) and the field dependence of the transformation temperature(dT/dH)are reported.
Trvalý link: http://hdl.handle.net/11104/0196860