Enhancement of the magnetocaloric effect driven by changes in the crystal structure of Al-doped GGG, Gd3Ga5−xAlxO12 (0 ≤x ≤5)

Sackville Hamilton, A. C. and Lampronti, G. I. and Rowley, S. E. and Dutton, S. E. (2014) Enhancement of the magnetocaloric effect driven by changes in the crystal structure of Al-doped GGG, Gd3Ga5−xAlxO12 (0 ≤x ≤5). Journal of Physics: Condensed Matter, 26 (11). p. 116001. ISSN 0953-8984, 1361-648X DOI 10.1088/0953-8984/26/11/116001

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Abstract

The Gd3Ga5−xAlxO12 (0 ≤ x ≤ 5) solid solution has been prepared using ceramic synthesis routes and the structural and magnetic properties were investigated using x-ray diffraction, magnetic susceptibility, χ, and isothermal magnetisation, M(H), measurements. Our results indicate a contraction of the unit cell and more significant antiferromagnetic interactions as x increases. Despite the decrease in the magnetic polarisation on the application of a field and the corresponding decrease in the change in the magnetic entropy, ΔS, we find that Gd3Al5O12 has a significantly higher observed (17%) and theoretical (14%) ΔS per unit mass than Gd3Ga5O12. The theoretical increase in ΔS per unit volume (7%) is offset by the increased antiferromagnetic interactions in Gd3Al5O12. The differences in ΔS are driven by a decrease in both the mass and the density as Al ions replace Ga ions. These results highlight the importance of changes to the crystal structure when considering materials for solid state magnetic cooling.

Item Type:	Article
Uncontrolled Keywords:	2014AREP; IA69;
Subjects:	03 - Mineral Sciences
Divisions:	03 - Mineral Sciences 99 - Other
Journal or Publication Title:	Journal of Physics: Condensed Matter
Volume:	26
Page Range:	p. 116001
Identification Number:	10.1088/0953-8984/26/11/116001
Depositing User:	Giulio Isacco Lampronti
Date Deposited:	20 Aug 2015 15:00
Last Modified:	20 Aug 2015 15:00
URI:	http://eprints.esc.cam.ac.uk/id/eprint/3447

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