Magnetic characterization of a hydrogen phase trapped inside deep dislocation cores in a hydrogen-cycled PdH x (x ≈ 4.5 × 10−4) single crystal

Autor: Andrei Lipson, A. Yu. Tsivadze, Carlos H. Castano, Boris F. Lyakhov, Brent J. Heuser
Rok vydání: 2006
Předmět:
Zdroj: Journal of Experimental and Theoretical Physics. 103:385-397
ISSN: 1090-6509
1063-7761
DOI: 10.1134/s1063776106090081
Popis: The magnetic characterization of Pd single crystals deformed by cycling in a hydrogen atmosphere has been performed. Based on evidence obtained from thermal desorption analysis, it is shown that the con- densed hydrogen phase formed inside deep dislocation cores in PdH x ( x = H/Pd ≈ 4.5 × 10 -4 ) is tightly bound with a Pd matrix. The activation energy of hydrogen desorption from these cores was found to be as high as e = 1.6 eV/H-atom, suggesting the occurrence of a strong band overlapping between Pd and H atoms. SQUID measurements carried out in a weak magnetic field ( H < 5.0 Oe) showed an anomalous diamagnetic contribu- tion to the DC and AC magnetic susceptibilities of the PdH x sample at T < 30 K resulting in the presence of the hydrogen phase. It is suggested that the anomalous diamagnetic response in PdH x is caused by the presence of a hydrogen dominant phase, tightly bound with a Pd matrix inside the dislocation cores (nanotubes).
Databáze: OpenAIRE