Journal article
Magneto-elastic coupling in La(Fe, Mn, Si)13Hy within the Bean-Rodbell model
Department of Energy Conversion and Storage, Technical University of Denmark1
Electrofunctional materials, Department of Energy Conversion and Storage, Technical University of Denmark2
Atomic Scale Materials Modelling, Department of Energy Conversion and Storage, Technical University of Denmark3
First order magnetic phase transition materials present a large magnetocaloric effect around the transition temperature, where these materials usually undergo a large volume or structural change. This may lead to some challenges for applications, as the material may break apart during field change, due to high internal stresses.
A promising magnetocaloric material is La(Fe, Mn, Si)13Hy, where the transition temperature can be controlled through the Mn amount. In this work we use XRD measurements to evaluate the temperature dependence of the unit cell volume with a varying Mn amount. The system is modelled using the Bean-Rodbell model, which is based on the assumption that the spin-lattice coupling depends linearly on the unit cell volume.
This coupling is defined by the model parameter η, where for η > 1 the material undergoes a first order transition and for η ≤ 1 a second order transition. We superimpose a Gaussian distribution of the transition temperature with a standard deviation σT, in order to model the chemical inhomogeneity.
Good agreement is obtained between measurements and model with values of η ∼ 1.8 and σ(T) = 1.0 K.
Language: | English |
---|---|
Publisher: | AIP Publishing LLC |
Year: | 2016 |
ISSN: | 21583226 |
Types: | Journal article |
DOI: | 10.1063/1.4944400 |
ORCIDs: | 0000-0003-3031-0926 , Nielsen, Kaspar Kirstein , Norby, Poul , Smith, Anders and Bahl, Christian R. H. |