Influence of Ni/Mn Concentration on the Magnetocaloric Effect in Ni43+xMn46-xSn11 (x = 0; 1) Heusler Alloys

Author / Creator

MMM 2020 (2020)

Conferences

MMM 2020 L4: Magneto-Elastic and Magneto-Caloric Materials III (2020)

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Summary

Discovery of the giant magnetocaloric effect (MCE) in interrmetallic Gd5(Si2Ge2) [1] led to an increase the interest in the materials with large MCE due to the possibility of their practical applic...

Discovery of the giant magnetocaloric effect (MCE) in interrmetallic Gd5(Si2Ge2) [1] led to an increase the interest in the materials with large MCE due to the possibility of their practical application as a working body [2] in magnetic cooling devices. Recently so-called shape-memory ferromagnets based on Heusler alloys Ni-Mn-Z (Z = Ga, In, Sn, Sb) began to be considered as the promising materials. For example, for Ni50Mn35Sn15 the value of △S = 14,2 J/(kgK) at 187 K in a magnetic field of 50 kOe [3]. The aim of this work was to study the effect of variation in chemical composition (the relative concentration Ni/Mn) on the MCE in Ni43+xMn46-xSn11 (x = 0; 1) Heusler alloys. Ingots were prepared by arc melting in an inert atmosphere and subsequently subjected to annealing at 1100 K for 24 h followed by furnace cooling. The elemental analysis and X-ray diffraction studies were performed. The magnetic and galvanomagnetic properties were measure at the Atomistitut, TU Wien using an MPMS XL7 (Quantum Design) SQUID magnetometer. The magnetic properties were measured in magnetic fields of up to 70 kOe in the temperatures range 150-330 K. As a result of this work it was established that the variation in the chemical composition does not lead to a significant change of the maximum value of the magnetocaloric effect (△S = 44 J/(kgK) and 40 J/(kgK) for Ni43Mn46Sn11 and Ni44Mn45Sn11, respectively), but shift its maximum (≈ 32 K). It was found that in the investigated alloys a change in the relative concentration Ni/Mn (and hence the e/a) does not significantly influence on the value of Curie temperature TC. The results of this work were obtained within the state assignment of the Ministry of Education and Science of the Russion Federation (theme "Spin" No. AAAA-A18-118020290104-2) and supported in part by RFBR grant (project No. 18-02-00739).References: [1] V.K. Pecharsky, K.A. Gschneider, Physical Review Letters, Vol. 78, p. 4494 (1997) [2] V.K. Pecharsky, K.A. Gschneider, Journal of Magnetism and Magnetic Materials, Vol. 200, p. 44 (1999) [3] T. Krenke, E. Duman, M. Acet, E.F. Wassermann, X. Moya, L. Mañosa, A. Planes, Nature Materials, Vol. 4, p. 450 (2005)

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