In-beam Mössbauer spectra of ⁵⁷Mn implanted into lithium aluminum hydride

In-beam Mössbauer spectra of ⁵⁷Mn implanted into LiAlH₄ were measured at different temperatures between 17 and 300 K. The Mössbauer spectrum measured at 17 K showed two sets of doublets, which were assigned to ⁵⁷Fe atoms at substitutional sites at Al³⁺ and Li⁺ sites. The Debye temperatures θ_M for the ⁵⁷Fe atoms at Al³⁺-substituted and Li⁺-substituted sites were estimated to be 194 K and 117 K, respectively. The assignments were confirmed by density functional theory calculations.