Hydrogen in R₂Fe₁₇ intermetallic compounds: Structural, thermodynamic, and magnetic properties

Authors

S. Wirth, Trinity College, Dublin, Ireland
Ralph Skomski, University of Nebraska-LincolnFollow
J.M.D. Coey, Trinity College, Dublin, Ireland

Date of this Version

June 1998

Comments

Published by Am Physical Soc. Phys. Rev. B 55 (1997) 5700-5707. Copyright 1997. Permission to use. http://www.aps.org/.

Abstract

The absorption and diffusion behavior of hydrogen in iron-rich rare-earth intermetallics of the type R₂Fe₁₇ (R=Y, Sm, Gd) and the resulting changes of their magnetic properties are investigated. Intermediate hydrogen concentration indicate the solid-solution character of the hydrides. From equilibrium and nonequilibrium absorption experiments net reaction energies, bulk diffusion constants, and surface barrier energies for Sm₂Fe₁₇ are determined and discussed. The low-temperature quantum diffusion is discussed for the hydride and the corresponding nitride. The interstitial modification changes drastically the crystalline electric field in the rare-earth intermetallics. For Sm₂Fe₁₇H₄ the crystalline electric-field parameter A₂₀=110 Ka₀^-2 is estimated from the anisotropy constants K₁ and K₂.