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Title: Influence of the starting temperature of calorimetric measurements on the accuracy of determined magnetocaloric effect

Availability of a restricted heat capacity data range has a clear influence on the accuracy of calculated magnetocaloric effect, as confirmed by both numerical simulations and experimental measurements. Simulations using the Bean-Rodbell model show that, in general, the approximated magnetocaloric effect curves calculated using a linear extrapolation of the data starting from a selected temperature point down to zero kelvin deviate in a non-monotonic way from those correctly calculated by fully integrating the data from near zero temperatures. However, we discovered that a particular temperature range exists where the approximated magnetocaloric calculation provides the same result as the fully integrated one. These specific truncated intervals exist for both first and second order phase transitions and are the same for the adiabatic temperature change and magnetic entropy change curves. Here, the effect of this truncated integration in real samples was confirmed using heat capacity data of Gd metal and Gd 5Si 2Ge 2 compound measured from near zero temperatures.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [2]
  1. Univ. de Sevilla, Sevilla (Spain)
  2. Ames Lab. and Iowa State Univ., Ames, IA (United States)
Publication Date:
Report Number(s):
IS-J-9623
Journal ID: ISSN 0304-8853; PII: S030488531733247X
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Journal of Magnetism and Magnetic Materials
Additional Journal Information:
Journal Volume: 457; Journal Issue: C; Journal ID: ISSN 0304-8853
Publisher:
Elsevier
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1434310

Moreno-Ramirez, L. M., Franco, V., Conde, A., Neves Bez, H., Mudryk, Y., and Pecharsky, V. K.. Influence of the starting temperature of calorimetric measurements on the accuracy of determined magnetocaloric effect. United States: N. p., Web. doi:10.1016/j.jmmm.2018.02.083.
Moreno-Ramirez, L. M., Franco, V., Conde, A., Neves Bez, H., Mudryk, Y., & Pecharsky, V. K.. Influence of the starting temperature of calorimetric measurements on the accuracy of determined magnetocaloric effect. United States. doi:10.1016/j.jmmm.2018.02.083.
Moreno-Ramirez, L. M., Franco, V., Conde, A., Neves Bez, H., Mudryk, Y., and Pecharsky, V. K.. 2018. "Influence of the starting temperature of calorimetric measurements on the accuracy of determined magnetocaloric effect". United States. doi:10.1016/j.jmmm.2018.02.083.
@article{osti_1434310,
title = {Influence of the starting temperature of calorimetric measurements on the accuracy of determined magnetocaloric effect},
author = {Moreno-Ramirez, L. M. and Franco, V. and Conde, A. and Neves Bez, H. and Mudryk, Y. and Pecharsky, V. K.},
abstractNote = {Availability of a restricted heat capacity data range has a clear influence on the accuracy of calculated magnetocaloric effect, as confirmed by both numerical simulations and experimental measurements. Simulations using the Bean-Rodbell model show that, in general, the approximated magnetocaloric effect curves calculated using a linear extrapolation of the data starting from a selected temperature point down to zero kelvin deviate in a non-monotonic way from those correctly calculated by fully integrating the data from near zero temperatures. However, we discovered that a particular temperature range exists where the approximated magnetocaloric calculation provides the same result as the fully integrated one. These specific truncated intervals exist for both first and second order phase transitions and are the same for the adiabatic temperature change and magnetic entropy change curves. Here, the effect of this truncated integration in real samples was confirmed using heat capacity data of Gd metal and Gd5Si2Ge2 compound measured from near zero temperatures.},
doi = {10.1016/j.jmmm.2018.02.083},
journal = {Journal of Magnetism and Magnetic Materials},
number = C,
volume = 457,
place = {United States},
year = {2018},
month = {2}
}