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Electronic Structure and Properties of Palladium and its Alloys
| Content Provider | Semantic Scholar |
|---|---|
| Author | Penson John B. Coles Phi, Duong Van |
| Copyright Year | 2005 |
| Abstract | Palladium is not ferromagnetic, not antiferromagnetic and not superconducting, but no one could call it a normal metal. If we exclude manganese and plutonium, there is no metal that exerts so powerful a fascination over anyone who has ever been concerned with its nature and properties; and since no one therefore can be impartial with respect to various theories of these it must be emphasised that this report on the Conference is a personal view. After the pioneer work of Mott in the I ~ ~ O S , palladium took up the role of the archetypical transition metal, that is one in which a narrow d-band containing some empty states was overlapped by a broad free-electron like s-band which dominated the conductivity. Since it is not ferromagnetic it was felt to be simpler than nickel, which it otherwise seemed to resemble as closely as or more closely than the Periodic Table would lead us to expect; and although this also meant that magnetisation evidence for the number of empty d-states was lacking, there was much indirect evidence (especially from alloys) to support the view that this number was close to the 0.6 per atom found for nickel. Discussions of magnetic properties were based on the high density of d-band states at the Fermi energy (indicated by the large value of the linear term in the low temperature specific heat), while the electrical properties were believed to be explicable in terms of s-like current carriers being scattered predominantly to d-like states. Much of this picture has recently been called into doubt. The de Haas-van Alphen data of Vuillemin and Priestly seem to require a number close to 0.36 for the s-electrons (and hence for the d-holes), galvanomagnetic data make a very large difference in s-electron and d-hole effective masses unlikely, and the very recent theories of persistent spin fluctuations of Doniach, Schrieffer and their co-workers imply that these make the traditional interpretation of the low temperature specific heat very uncertain. This last point should not be regarded as purely hypothetical, for experimental studies of the effects of magneticmoment-bearing impurities by susceptibility, neutron scattering, and paramagnetic resonance techniques have agreed in indicating that exchange interaction effects in the d-band of palladium can by no means be regarded as a small perturbation, and hence low-lying excitations of a non single-particle type must be considered. The Conference had as its aim an examination of the new situation and as its achievement a reconciliation of much of the traditional view with the new theories and results. It seemed as if the final doubts of those who hesitated to believe in ‘paramagnons’ (the |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.technology.matthey.com/wp-content/uploads/pdf/pmr-v11-i3-109-111.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
