Magnetic Properties of Palladium and Palladium–Platinum Alloy of Various Hydrogen Content

Abstract

Magnetic properties of palladium and palladium-platinum alloy (Pd-Pt) of different hydrogen content were measured in a hydrogen atmosphere at ambient temperature using a superconducting quantum interference device (SQUID) magnetometer. It was found that the magnetic susceptibility of Pd and Pd-Pt alloy decreased with increasing hydrogen content. These results were attributed to a change in the electronic structure of the valence band. Increasing hydrogen content in Pd and Pd-Pt alloy causes the Fermi level to rise and the density of states at Fermi level to decrease. Since the magnetic susceptibility is proportional to the density of states at the Fermi level, the magnetic susceptibility decreases with increasing hydrogen content. The magnetic susceptibility of Pd-Pt was smaller than that of Pd over the whole hydrogen content range. This was ascribed to the higher position of the Fermi level of Pd-Pt than that of Pd.

Thermodynamic and Magnetic Properties of Pd<SUB>0.93</SUB>Ag<SUB>0.07</SUB> Hydride

“…7. This is the same as that of Pd 15,16,21,28) 3.3 Relationship between p-c curve and magnetic susceptibility The end of the plateau region coincides with the disappearance of the susceptibility as seen in Figs. 2, 3 and 7.…”

“…Details of the vessel have been described in a previous paper. 16) A columnar fragment of Pd 0:93 Ag 0:07 0.1 g in weight was introduced into the copper tube and fixed there with glass beads. To activate the Pd 0:93 Ag 0:07 , the vessel was attached to a high vacuum system and evacuated to less than 1 Â 10 À5 Pa. Activation was carried out by heating the sample at 473 K for 2 hours under vacuum.…”

“…14) Such a change in susceptibility with absorbing hydrogen has been reported for palladium by several investigators. 8,15,16) The measurements can be carried out under a hydrogen atmosphere, although the Fermi level itself can not be determined by the susceptibility measurement.…”

Superconductivity of platinum hydride

“…This Pd 4d and H 1s electron hybridization results in the reduction in electron density of states (e-DOS) at a Fermi level (E F ), leading to the loss of paramagnetic susceptibility. PdH x becomes nonmagnetic with hydrogen composition x = H/Pd greater than 0.62 [9,10]. At the same time, the coupling between conduction electrons and the soft-optic mode, which is related to local hydrogen vibrations, is enhanced [7,8].…”

Sensing hydrogen in the gas phase using ferromagnetic Pd–Co films

“…However, the magnetic susceptibility of Pd is very small [3], and can barely be quantified. Recently, the magnetic susceptibilities of Pd alloys have been reported as a function of the hydrogen concentration in bulk [5][6][7][8][9]. In these Pd alloys, the Pd-Co alloys with Co concentrations above 8 atom% exhibited ferromagnetic behavior [10] and the magnetic susceptibility decreased significantly with the hydrogen concentration in the bulk [9].…”