Solid-State Reaction and Vacancy-Type Defects in Bilayer Fe/Hf Studied by the Slow Positron Beam

K Yamada,K Nozawa,T Nagata,T Sasaki,F Komori,R Suzuki,T Ohdaira,I Kanazawa

doi:10.4236/jamp.2015.32034

Abstract

The positron annihilation lifetimes and the Doppler broadening by slow positron beam are measured in thin Fe films with thickness 500 nm, a thin Hf film with thickness 100 nm, and the bilayer Fe (50 nm)/Hf (50 nm) on quartz glass substrate. We have analyzed the behavior in vacancy-type defects in each layer through some deposition temperatures and annealing. It is observed that the thin Fe film, the thin Hf film, and the bilayer Fe (50 nm)/Hf (50 nm) already contain many vacancy-type defects. We have investigated the change of densities of the vacancy-carbon complex and the small vacancy-cluster with carbons, through solid-state amorphization of Fe (50 nm)/Hf (50 nm) bilayer.

Highlights

Schwarz and Johnson [1] first have reported that isothermal annealing of thin film multilayers of two different crystalline metals (La and Au) can lead to the formation of an amorphous alloy
How to cite this paper: Yamada, K., Sasaki, T., Nagata, T., Kanazawa, I., Suzuki, R., Ohdaira, T., Nozawa, K. and Komori, F. (2015) Solid-State Reaction and Vacancy-Type Defects in Bilayer Fe/Hf Studied by the Slow Positron Beam
It is found that the values of S-parameter in the bilayer annealed for 4 hours at 800 K decrease much in the region of the incident energy from ~0 to ~13 keV, in comparison with those of as-deposited bilayer. This indicates that vacancy-type defects in both Fe and Hf layers annihilate much during annealing for 4 hours at 800 K. These results show that diffusion of Fe component is much faster than that of Hf component

Summary

Introduction

Schwarz and Johnson [1] first have reported that isothermal annealing of thin film multilayers of two different crystalline metals (La and Au) can lead to the formation of an amorphous alloy. Amorphization by mechanical alloying, a kind of solid-state amorphization, has been discovered [2]. It has been proposed that a multilayer structure, which is created in the initial stage of mechanical allying, plays an important role in amorphization [3]. The anomalously fast diffusion of one component and a large negative heat of mixing in the alloy are important factors in solid-state amorphization [4]. (2015) Solid-State Reaction and Vacancy-Type Defects in Bilayer Fe/Hf Studied by the Slow Positron Beam.

Methods

Results

Conclusion