Magnetic properties of Fe2GeMo3N; an experimental and computational study

Reference:

Battle, P. D., Sviridov, L. A., Woolley, R. J., Grandjean, F., Long, G. J., Catlow, C. R. A., Sokol, A. A., Walsh, A. and Woodley, S. M., 2012. Magnetic properties of Fe2GeMo3N; an experimental and computational study. Journal of Materials Chemistry, 22 (31), pp. 15606-15613.

Related documents:

Official URL:

http://dx.doi.org/10.1039/c2jm32574h

Abstract

A polycrystalline sample of Fe2GeMo3N has been synthesized by the reductive nitridation of a mixture of binary oxides in a flow of 10% dihydrogen in dinitrogen. The reaction product has been studied by magnetometry, neutron diffraction and Mössbauer spectroscopy over the temperature range 1.8 ≤ T/K ≤ 700. The electronic structure and magnetic coupling have been modelled by Density Functional Theory (DFT) and Monte Carlo methods. Fe2GeMo3N adopts the cubic η-carbide structure with a = 11.1630(1) Å at 300 K. The electrical resistivity was found to be [similar]0.9 mΩ cm over the temperature range 80 ≤ T/K ≤ 300. On cooling below 455 K the compound undergoes a transition from a paramagnetic to an antiferromagnetic state. The magnetic unit cell contains an antiferromagnetic arrangement of eight ferromagnetic Fe4 tetrahedra; the ordered atomic magnetic moments, 1.90(4) μB per Fe atom at 1.8 K, align along a <111> direction. DFT predicts an ordered moment of 1.831 μB per Fe. A random phase approximation to the DFT parameterised Heisenberg model yields a Néel temperature of 549 K, whereas the value of 431 K is obtained in the classical limit for spin. Monte Carlo calculations confirm that the experimentally determined magnetic structure is the lowest-energy antiferromagnetic structure, but with a lower Néel temperature of 412 K. These results emphasise the potential of these computational methods in the search for new magnetic materials.

Export

Actions (login required)