Extraordinary Responsive Rare Earth Magnetic Materials
Mahmud Khan, Hui Wang, Junding Zou
A major goal of this research is to uncover the underlying electronic, atomic and microscopic interactions that result in an extraordinarily strong coupling between the magnetic and crystal lattices and remarkable responsiveness to both strong (temperature and pressure) and weak (magnetic field) stimuli in some rare earth intermetallic materials. It will be achieved by focusing on the state-of-the-art synthesis, processing and characterization, combined with theory, modeling and computations gauged and refined against reliable experimental data.
The following systems have been selected as model candidates: GdNi and other equiatomic RM compounds (R is a rare earth metal and M is a 3d transition metal or a main Group 14 element), RCo2, La(Fe1‑xSix)13 and hydrides La(Fe1‑xSix)13Hy, and R5T4 compounds (T is a main Group 14 element). These materials exhibit a number of diverse and unique properties associated with magnetic ordering alone, magneto-volume, itinerant electron metamagnetic, and magnetic-martensitic transformations, respectively, which may or may not be driven by a reversible breaking and reforming of specific chemical bonds.
Development and validation of phenomenological models of transformations that range from magneto-volume to magnetic-martensitic is another goal, thus guiding future discoveries of material systems exhibiting strong reactions to small changes of magnetic field, with temperature and pressure providing additional sources of stimulation.
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