The giant effect of magnetic ordering on a sound velocity in a sigma-Fe55Cr45 alloy

We studied atomic dynamics of sigma-Fe(100-x)Cr(x) (x=45 and 49.5) alloys using nuclear inelastic scattering of synchrotron radiation. For the sigma-Fe55Cr45 alloy, the derived reduced iron-partial density of phonon states reveal a huge difference in the low-energy region between magnetic and paramagnetic states. The latter implies a ca.36% increase of the sound velocity in the magnetic phase, which testifies to a magnetically-induced hardening of the lattice.Comment: 8 pages, 3 figures, 17 reference

Electronic structure of the sigma-phase in paramagnetic Fe-V alloys. Experimental and theoretical study

The electronic structure of $\sigma$-phase Fe$_{100-x}$V$_x$ compounds with 33.3 $\le x \le 60.0$ was calculated from the charge self-consistent Korringa-Kohn-Rostoker method. For the first time, charge densities $\rho_A(0)$ and electric field gradients were determined at Fe nuclei, that occupy five nonequivalent lattice sites. The highest $\rho_A(0)$ values were found on sites A and D, and the lowest one on site B, the difference ranging between 0.162 and 0.174 $\it s$-like electrons per Fe atom for $x = 33.3$ and $x = 60$, respectively. The calculated quantities combined with experimentally determined site occupancies were successfully applied to analyze $^{57}$Fe M\"ossbauer spectra recorded on a series of 8 samples in a paramagnetic state.Comment: 4 pages, 4 figures, 15 reference