Magnetic refrigeration: unusual interplay between magnetism and chemical bonding revealed

snip 20170530173018Magnetic refrigeration is based on the magnetocaloric effect, which is associated with the temperature change of a material when placed in a magnetic field. X-ray techniques and DFT calculations were used to investigate the first-order magnetoelastic transitions of Fe2P-based materials. The electron density was studied across the transition and a distinct charge redistribution around the Fe atoms at the ferromagnetic transition was found for the paramagnetic state which deforms the unit cell. DFT calculations show a simultaneous decrease in the magnetic moment of Fe, indicating that there is competition between the magnetic moment and covalent bonding.

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