Influence of Thermal and Magnetic History on Direct DTad Measurements of Ni49+xMn36-xIn15 Heusler Alloys

In the present work, using Heusler Ni49+xMn36-xIn15 (with x = 0 and 0.5) alloys, it is shown that the choice of the appropriate measurement protocol (erasing the prior state of the sample in between experiments) in DTad first shot characterization is crucial for obtaining reliable results. Unlike indirect measurements, for which incorrect protocols produce overestimates of the characteristics of the material, erroneous direct measurements underestimate DTad in the region close to its first order phase transition. The error in DTad is found to be dependent on the temperature step used, being up to ~40% underestimation, including a slight shift in its peak temperature.