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

## Abstract

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 _{5}Si _{2}Ge _{2} compound measured from near zero temperatures.

- Authors:

- Univ. de Sevilla, Sevilla (Spain)
- Ames Lab. and Iowa State Univ., Ames, IA (United States)

- Publication Date:

- Research Org.:
- Ames Laboratory (AMES), Ames, IA (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1434310

- Report Number(s):
- IS-J-9623

Journal ID: ISSN 0304-8853; PII: S030488531733247X

- Grant/Contract Number:
- AC02-07CH11358

- Resource Type:
- Journal Article: 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

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 36 MATERIALS SCIENCE

### Citation Formats

```
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., 2018.
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. Tue .
"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 = {Tue Feb 27 00:00:00 EST 2018},

month = {Tue Feb 27 00:00:00 EST 2018}

}