Au, Ir, Pt, Rh, Ti, and W foils were implanted with ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ ions with doses from ${10}^{15}$ to 5×${10}^{16}$ ions/${\mathrm{cm}}^2$ and studied at room temperature by conversion electron Mössbauer spectroscopy. It has been proved that the macroscopic heat of solution of Fe in respective metals is a primary parameter determining the state of implanted specimens. For an attractive Fe-Fe potential the iron implants are observed in the form of aggregates, while for a repulsive Fe-Fe potential, they are not distinguishable in Mössbauer spectra. Molecular-dynamics simulations showed that the final arrangement of atoms within a thermal spike is maintained during about 1.2 ps.

The series of Mn_2−xFe_xP_1−ySi_y types of compounds form one of the most promising families of magnetocaloric materials in term of performances and availability of the elemental components. Potential for large scale application needs to optimize the synthesis process, and an easy and rather fast process here described is based on the use of two main type of precursors, providing the Fe-P and Mn-Si proportions. The series of Mn_2−xFe_xP_1−ySi_y compounds were synthesized and carefully investigated for their crystal structure versus temperature and compared interestingly with earlier results. A strong magnetoelastic effect accompanying the 1st order magnetic transition—as well as the parent phosphide–arsenides—was related to the relative stability of both the Fe magnetic polarization and the Fe–Fe exchange couplings. In order to better understand this effect, we propose a local distortion index of the non-metal tetrahedron hosting Fe atoms. Besides, from Mn-rich (Si-rich) to Fe-rich (P-rich) compositions, it is shown that the magnetocaloric phenomenon can be established on demand below and above room temperature. Excellent performance compounds were realized in terms of magnetic entropy ΔS_m and adiabatic temperature ΔT_ad variations. Since from literature it was seen that the magnetic performances are very sensitive to the synthesis process, correspondingly here a new effective process is proposed. Mössbauer spectroscopy analysis was performed on Mn-rich, equi-atomic Mn-Fe, and Fe-rich compounds, allowing determination of the distribution of hyperfine fields setting on Fe in the tetrahedral and pyramidal sites, respectively. Electronic structure calculations confirmed the scheme of metal and non-metal preferential ordering, respectively. Moreover, the local magnetic moments were derived, in fair agreement with both the experimental magnetization and the Fe contributions, as determined by Mössbauer spectroscopy.

[Re(CN)₈]³⁻ and [W(CN)₈]³⁻ compete in shaping the phase transition and magnetic interactions in trimetallic {Fe₉[Re(CN)₈]_6−x[W(CN)₈]_x} clusters via tuning of the valence electron distribution and mobility.