Controlling magnetism and magneto-structural phase transformation in rare earth containing materials

In rare earth element based materials the alloyed p-block elements provide chemical formation and stability, and control magnetism exhibited by rare earths. We report here two examples of how non-magnetic elements substitution pinpointed enhanced and controlled magnetism and phase transformation. First example is Eu₂In, in which the Eu 5d states strongly hybridize with the In 5p states exhibiting large exchange splitting in ferromagnetic configuration. This unexpectedly high exchange splitting is the root cause of the sharp paramagnetic to ferromagnetic transition [1]. The other example is scandium substituted Gd₅Ge₄. Total energy calculations show that Sc favors the Gd atoms located inside the slabs and predict a stable ferromagnetic ground state with the 20 atomic % Sc substituted Gd₅Ge₄. The predicted phase is Pu₅Rh₄-type which is intermediate between the Sm₅Ge₄-type and Gd₅Si₄-type. The delocalized 3d electronic states of Sc strongly hybridize with delocalized 5d electronic states of Gd, thus promoting indirect interslab 4f-4f exchange interactions [2].

[1] Nature Comm. 9, 2925 (2018)
[2] Chem. Mater. 29, 3962 (2017)