INFLUENCE OF COPPER ON THE MAGNETIC AND MAGNETOCALORIC PROPERTIES OF NI50MN34IN14B ALLOYS
Abdiel Quetz1, Sudip Pandey1, Anil Aryal1, Igor Dubenko1, Tapas Samanta2, Shane Stadler2, Naushad Ali1.
1Southern Illinois University Carbondale, Carbondale, IL, 2Louisiana State University, Baton Rouge, LA.
The magnetocaloric and thermomagnetic properties of the Ni50Mn34-xCuxIn14B (x = 0, 0.75, 1.25, 2.00) system have been studied by room temperature X-ray diffraction, differential scanning calorimetry (DSC), and magnetization measurements. Partial substitution of Cu for Mn in Ni50Mn34-xCuxIn14B results in a shift of TM to lower temperature while TC remains unchanged at around 320 K. A second order transition was observed from a paramagnetic austenitic (PA) to a ferromagnetic austenitic (FA) phase at TC = 320 K, and first order magnetostructural transition (MST) was observed from a ferromagnetic austenitic (FA) to low magnetization martensitic phase at TM = 220 (for x = 1.25). The values of the latent heat (L = 9.4 J/g) and corresponding total entropy changes (ST = 29.7 J/kg K) have been evaluated using DSC measurements. The magnetic entropy change value is comparable to those of well-known giant magnetocaloric materials, such as Gd5Si2Ge2, MnFeP0.45As0.55, and Ni50Mn37Sn13. A concentration-dependent phase diagram of transition temperatures (magnetic, structural, and magnetostructural) has been generated using magnetic, XRD, and DSC data. The role of magnetic and structural changes on transition temperatures is discussed. (This work was supported by the Office of Basic Energy Sciences, Materials Science and Engineering Division of the U.S. Department of Energy; USDOE-DE-FG02-06ER46291 and DE-FG02-13ER46946)