Share

IIR document

Failure of the Maxwell relation for the quantification of caloric effects in ferroic materials.

Number: sect. 2

Author(s) : NIEMANN R., HECZKO O., SCHULTZ L., et al.

Summary

Giant caloric effects were reported in elasto-, electro- and magnetocaloric materials near phase transformations. Commonly, their entropy change is indirectly evaluated by a Maxwell relation. The authors report the fundamental failure of this approach and they analyze exemplarily the Ni-Mn-Ga magnetic shape memory alloy. An applied field results in magnetically induced reorientation of martensitic variants, which form during the phase transformation. This results in a spurious magnetocaloric effect, which only disappears when repeating the measurement. This failure is universal as the vector character of the applied field is not considered in the common scalar evaluation of a Maxwell relation.

Available documents

Format PDF

Pages: 219-226

Available

  • Public price

    20 €

  • Member price*

    Free

* Best rate depending on membership category (see the detailed benefits of individual and corporate memberships).

Details

  • Original title: Failure of the Maxwell relation for the quantification of caloric effects in ferroic materials.
  • Record ID : 30005540
  • Languages: English
  • Source: 5th International Conference on Magnetic Refrigeration at Room Temperature (Thermag V). Proceedings: Grenoble, France, September 17-20, 2012.
  • Publication date: 2012/09/17

Links


See other articles from the proceedings (70)
See the conference proceedings

Indexing