The magnetic and magnetothermal properties of holmium single crystal have been investigated from 4.2 to 300 K in magnetic fields up to 100 kOe using magnetization and heat capacity data measured along the easy magnetization direction, which is the crystallographic b-axis, i.e. [112¯0] direction. The magnetic phase diagram of Ho has been refined by examining data measured using a high purity single crystal.

The NiMnInSi Heusler alloy family is analyzed, and a self-similarity based method is used to analyze the first-order transition of Ni-Mn Heusler alloys. This method is appropriate to determine magnetic characteristics of the Magnetocaloric Effect providing that there is sufficient separation in their phase transition temperatures. A temperature scaling methodology is used to model the cluster compositions in the mixed-state regions where two stable magnetic states co-exist. The various descriptions and classifications of these transitions, however, are not critical to this analysis.

No abstract

The latent heat linked with the first-order transformation of a NiMnIn Heusler alloy has been studied through direct measurements of the adiabatic temperature change, ΔTad, during magnetization process. The experimental procedure used guarantees independent data points and negates any contribution of hysteretic losses to the magnetocaloric effect. Thus, the differences between the magnitudes of ΔTad measurements during the magnetization with the initial temperature change directions from low-to-high and high-to-low are solely attributed to the latent heat exchange, which accompanies the irreversible structural first-order transformation. An estimate of the latent heat inducing such differences is about 0.292 J/g.