Artículo
Enhanced cryogenic magnetocaloric effect in Eu8Ga16Ge30 clathrate nanocrystals
Autor/es | Biswas, Anis
Chandra, Sayan Rout Stefanoski, S. Blázquez Gámez, Javier Sebastián Ipus Bados, Jhon Jairo Conde Amiano, Alejandro Phan, Manh Huong Franco García, Victorino Nolas, George S. Srikanth, Hariharan |
Departamento | Universidad de Sevilla. Departamento de Física de la Materia Condensada |
Fecha de publicación | 2015 |
Fecha de depósito | 2016-02-01 |
Publicado en |
|
Resumen | We observe an enhanced magnetic entropy change (
D
S
M
) at cryogenic temperatures (T
<
20 K)
in Eu
8
Ga
16
Ge
30
clathrate (type-I) nanocrystals prepared by a ball milling method. With reduction
in the ... We observe an enhanced magnetic entropy change ( D S M ) at cryogenic temperatures (T < 20 K) in Eu 8 Ga 16 Ge 30 clathrate (type-I) nanocrystals prepared by a ball milling method. With reduction in the crystal size to 15 nm, D S M is enhanced at low temperatures, reaching the highest value ( 10 J/kg K) at 5 K for a field change of 5 T. For all samples investigated, there is a cross-over tem- perature ( 25 K) in D S M (T) above which D S M decreases with crystal size, opposite to that observed at low temperatures. A careful analysis of the magnetic and magnetocaloric data reveals that as the crystal size decreases the magnetic interaction between Eu 2 þ ions on the Eu2 site gov- erning the primary ferromagnetic transition at 35 K becomes gradually weaker, in effect, altering the interaction between Eu 2 þ ions occupying the Eu1 and Eu2 sites responsible for the secondary ferromagnetic transition at 15 K. As a result, we have observed a strong change in magnetization and the enhancement of D S M at low temperature. |
Ficheros | Tamaño | Formato | Ver | Descripción |
---|---|---|---|---|
Enhanced cryogenic.pdf | 1.176Mb | [PDF] | Ver/ | |