Determination of exchange interactions of solid solutions of Mn2+in Pd and Pd hydride through ESR experiments

Abstract

The authors present ESR data concerning manganese impurities dissolved in pure palladium and in the beta phase of palladium hydride. In the pure Pd matrix, the behaviour of the resonance of the Mn impurities in low-concentration alloys shows that: (i) the resonance is bottlenecked, (ii) the g factors of the conduction electrons and Mn2+ ions are different, (iii) the conduction electron-manganese coupling is strongly positive with a Korringa shift triangle gK/gi approximately=0.5 which agrees with the presence of a giant moment on the manganese ions. In the hydrides they observe a smaller but negative g shift, in agreement with the familiar covalent mixing interaction and some indication of a bottlenecked resonance. The spatial dependence of the conduction electron-manganese interaction is analysed using the ESR data and the residual resistivity. The influence of indirect and direct Mn-Mn interactions on the ESR is observed and discussed for the more concentrated alloys.