ZhETF, Vol. 130,
p. 442 (September 2006)
(English translation - JETP,
Vol. 103, No. 3,
available online at www.springer.com
MAGNETIC CHARACTERIZATION OF A HYDROGEN PHASE TRAPPED INSIDE DEEP DISLOCATION CORES IN A HYDROGEN-CYCLED PdHx (x\approx 4.5\cdot 10-4) SINGLE CRYSTAL
Lipson A.G., Heuser B.J., Castano C.H., Lyakhov B.F., Tsivadze A.Yu.
Received: March 23, 2006
PACS: 74.78.Fk, 74.10.+v, 61.72.-y
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 condensed hydrogen phase formed inside deep dislocation cores in PdHx () 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 contribution to the DC and AC magnetic susceptibilities of the PdHx sample at T<30 K resulting in the presence of the hydrogen phase. It is suggested that the anomalous diamagnetic response in PdHx is caused by the presence of a hydrogen dominant phase, tightly bound with a Pd matrix inside the dislocation cores (``nanotubes'').