Search for instability-induced amorphization in deuterated ErFe2
Abstract
Experimental evidence–in the form of a specific-heat anomaly–for instability-induced amorphization of ErFe2 by hydrogenation was recently reported by Fecht, Fu, and Johnson [Phys. Rev. Lett. 64, 1753 (1990)]. We have attempted to study this anomaly by in situ elastic neutron diffraction and differential-scanning-calorimetry (DSC) measurements of deuterated ErFe2 below and above the reversible, endothermic, λ-shaped enthalpy signal that they found at ∼200 °C. Our combined diffraction and DSC results reveal that the amorphization transition is irreversible, strongly exothermic and occurs only at a significantly higher temperature than that of the specific-heat anomaly. Rather than resulting from an underlying instability of the crystalline phase, amorphization occurs as a by-product of short-range clustering of the Er and Fe atoms, which is driven by the creation of energetically more favorable sites for the deuterium atoms.
Additional Information
©1993 The American Physical Society. Received 15 March 1993. We are grateful to the staffs of MURR and of the machine shop of the Department of Physics at the University of Missouri-Columbia for their expert assistance. It is a pleasure to acknowledge useful discussions with Dr. Z. Fu, Dr. R. Birringer, and Professor H.J. Fecht. Financial support for these experiments came from the U.S. Department of Energy under Contract Nos. DEFG05-89ER75511 (x-ray-diffraction measurements) and DE-FG03-86ER25242.Files
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2007-08-31Created from EPrint's datestamp field
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