Calorimetric investigation of the magnetocaloric effect in Ni 45 Co 5 Mn 37.5 In 12.5

• Published in: Journal of physics. D, Applied physics Applied physics, 2012-06, Vol.45 (25), p.255001
• Main Authors: Guillou, F, Courtois, P, Porcar, L, Plaindoux, P, Bourgault, D, Hardy, V
• Format: Article
• Language: English
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/45/25/255001

A calorimetric investigation of a Ni 45 Co 5 Mn 37.5 In 12.5 single crystal has been carried out by combining differential scanning calorimetry (DSC) and heat capacity ( C ) measurements. The martensitic transition showing a first-order character spread over a wide temperature range, a specific measuring technique of C ( T ) has been developed. This method—based on a time-resolved analysis of successive heating pulses—was found to yield an entropy change at the transition (Δ S tr ) that is very close to that derived from DSC. To investigate the magnetocaloric effect, both the isothermal entropy change Δ S T and the adiabatic temperature change Δ T ad were derived from heat capacity curves recorded in a series of magnetic fields up to 7 T. The maximum values of Δ S T ( T , B ) were observed to be in accordance with those determined from the Maxwell equation. Furthermore, maximum values of Δ T ad ( T , B ) resulting from the application of 2 T, 5 T and 7 T were found to be equal to −2.3 K, −6.1 K and −9.4 K, respectively.