Vibrational thermodynamics ofFe90Zr7B3nanocrystalline alloy from nuclear inelastic scattering

Abstract

Recently we determined the iron-partial density of vibrational states (DOS) of nanocrystalline ${\text{Fe}}_{90}{\text{Zr}}_{7}{\text{B}}_{3}$ (Nanoperm), synthesized by crystallization of an amorphous precursor, for various stages of nanocrystallization separating the DOS of the nanograins from that of the interfaces [S. Stankov, Y. Z. Yue, M. Miglierini, B. Sepiol, I. Sergueev, A. I. Chumakov, L. Hu, P. Svec, and R. R\uffer, Phys. Rev. Lett. 100, 235503 (2008)]. Here we present quantitative analysis of the evolution of various thermoelastic properties calculated from DOS such as mean-force constant, mean atomic displacement, vibrational entropy, and lattice specific heat as the material transforms from amorphous, through nanocrystalline, to fully crystallized state. The reported results shed new light on the previously observed anomalies in the vibrational thermodynamics of nanocrystalline materials.