CONDUCTANCE ELECTRON-SPIN-RESONANCE OF PD AND PDHX PARTICLES IN ZEOLITE NAY

The conduction electron spin resonance (CESR) of small Pd and PdH(x) particles has been measured at g = 2.190 +/- 0.002. This isotropic resonance of the metal could be distinguished from those due to ionic Pd centers which are anisotropic, and also because its properties are very similar to the magnetic properties of Pd metal. For example, the strong paramagnetic susceptibility of Pd is known to decrease with increasing H content. The CESR, whose intensity is proportional to the susceptibility, also decreases with H sorption. Furthermore, the addition of oxygen has been reported to increase the Curie temperature of Pd-Fe dilute alloys. Here the addition of oxygen was found to shift and broaden the CESR. It also induces spin-glass behavior in the Pd particle assembly with a freezing temperature near 12 K, as seen by the temperature dependence of the CESR susceptibility.