Presentation Information
[P2-16]Magnetic and magnetocaloric effect on the high entropy alloys (Y0.2La0.2Gd0.2Pr0.2Er0.2)Al2 and (Y0.2La0.2Nd0.2Pr0.2Er0.2)Al2
*Bruno Alho1, Paula Ribeiro1, Rodrigo de Oliveira1, Alexandre Carvalho1,2,3, Pedro von Ranke1, Cesar Silva2, Marcos Vinícius Puydinger4, Erik Usuda2, Ricardo Silva2 (1. Rio de Janeiro State University (Brazil), 2. Universidade Federal de São Paulo (Brazil), 3. Universidade Estadual de Maringá (Brazil), 4. Universidade Estadual de Campinas (Brazil))
Keywords:
high entropy alloys,magnetocaloric effect,crystalline electrical field
In recent years, high entropy alloys (HEAs) have garnered escalating interest owing to their distinctive physical and chemical attributes, particularly their potential for magnetocaloric applications. The magnetocaloric effect, a phenomenon characterized by the temperature change in a magnetic material under the influence of an applied magnetic field, has been observed prominently in HEAs. This is attributed to their intricate microstructures and substantial magnetic entropy change. As a result, HEAs emerge as compelling prospects for deployment in magnetic refrigeration, offering a more environmentally friendly and energy-efficient alternative to conventional vapor compression refrigeration systems [1].
In this study, we developed a theoretical model for configurational HEAs based on rare earth elements of the type (R1,R2,R3,R4,R5)Al2. The calculations are based on a microscopic model Hamiltonian that incorporates contributions from the Zeeman effect, crystalline electric field anisotropy, and exchange interactions between the rare-earth sublattices (e.g., R1- R1, R1- R2, R1- R3). We prepared and characterized two new compounds: (Y0.2La0.2Gd0.2Pr0.2Er0.2)Al2 and (Y0.2La0.2Nd0.2Pr0.2Er0.2)Al2. The first exhibits a magnetic transition temperature around 34 K and a magnetization of 2.07 μB/f.u. at 70 kOe, which is significantly lower than the expected value of 3.84 μB/f.u., considering all magnetic moments aligned in the direction of the applied magnetic field. The second compound shows a transition temperature around 19 K and a magnetization of 1.24 μB/f.u. at 70 kOe, which is also much lower than the expected value (3.09 μB/f.u.), considering the same alignment of the magnetic moments. Soon, we will apply the theoretical model to the experimental data of these new configurational high-entropy compounds.
Reference:
[1] J. Y. Law and V. Franco, J. Mater. Res. 38 (2023), 37-51.
In this study, we developed a theoretical model for configurational HEAs based on rare earth elements of the type (R1,R2,R3,R4,R5)Al2. The calculations are based on a microscopic model Hamiltonian that incorporates contributions from the Zeeman effect, crystalline electric field anisotropy, and exchange interactions between the rare-earth sublattices (e.g., R1- R1, R1- R2, R1- R3). We prepared and characterized two new compounds: (Y0.2La0.2Gd0.2Pr0.2Er0.2)Al2 and (Y0.2La0.2Nd0.2Pr0.2Er0.2)Al2. The first exhibits a magnetic transition temperature around 34 K and a magnetization of 2.07 μB/f.u. at 70 kOe, which is significantly lower than the expected value of 3.84 μB/f.u., considering all magnetic moments aligned in the direction of the applied magnetic field. The second compound shows a transition temperature around 19 K and a magnetization of 1.24 μB/f.u. at 70 kOe, which is also much lower than the expected value (3.09 μB/f.u.), considering the same alignment of the magnetic moments. Soon, we will apply the theoretical model to the experimental data of these new configurational high-entropy compounds.
Reference:
[1] J. Y. Law and V. Franco, J. Mater. Res. 38 (2023), 37-51.
