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00925njm 22002777a 4500 dc Cepeda-Jiménez, C.M. author Beltrán Fínez, Juan Ignacio author Hernando Grande, Antonio author García, M.A. author Ynduráin, F. author Zhilyaev, A. author Perez-Prado, M.T. author 2017-01-15 This work demonstrates that room temperature (RT) ferromagnetism might be triggered in pure hafnium (Hf), a classic paramagnet, by severe plastic deformation (SPD) via high pressure torsion (HPT). The origin of this phenomenon is elucidated by a combined approach including density functional theory (DFT) calculations and transmission electron microscopy (TEM). In particular, it is shown that the elastic lattice distorsions induced in pure Hf as a consequence of grain refinement down to the nanocrystalline regime by HPT lead to the development of a new monoclinic crystalline structure that exhibits a spontaneous magnetization at RT. DFT calculations are utilized to prove that local stretching of the original pure Hf hexagonal close packed (hcp) lattice along specific pyramidal directions, due to the presence of internal stresses in the deformed nanostructure, may give rise to the emergence of the monoclinic phase, which is endowed with a net magnetic moment. An excellent agreement is found between DFT calculations and experimental TEM observations, which provide a first evidence of the presence of the pure Hf monoclinic crystal lattice. This work shows that SPD may constitute a viable, yet widely unexplored, strategy to tune the magnetic properties and, in particular, to induce RT ferromagnetism in bulk non-magnetic metals. Cepeda-Jiménez, C. M., et al. «Tuning the Magnetic Properties of Pure Hafnium by High Pressure Torsion». Acta Materialia, vol. 123, enero de 2017, pp. 206-13. DOI.org (Crossref), https://doi.org/10.1016/j.actamat.2016.10.052. 1359-6454 10.1016/j.actamat.2016.10.052 https://hdl.handle.net/20.500.14352/94469 1873-2453 https://doi.org/10.1016/j.actamat.2016.10.052 Tuning the magnetic properties of pure hafnium by high pressure torsion