Segregation of Co-57 atomic probe in the core of crystallite-conjugation regions in noble metals

The new method of studying the structure and various physical properties of the core of crystallite-conjugation regions (CCRs) developed in our previo us works [Usp. Fit. Nauk, 160 (1) 99-139 (1990); Phys. Rev. B, 49 (14) 9376 -9399 (1994)] was used to extract information on atomic segregates localize d in two qualitatively different regions of polycrystals: in the core of CC Rs and in two-dimensional lattice regions adjacent to the CCRs, In this wor k, we present and discuss the results of the investigations of segregation of atomic probes Co-57 in the core of CCRs in three noble metals (Pd, Pt, a nd Au), The interaction of the Co-57 AP with the core of CCRs in metals is similar to its interaction with vacancies, since the CCR core, like vacanci es in metals, has an excess volume and a negative charge. In all three nobl e metals indicated above, the Co-57 atomic probe does not segregate at CCRs , The behavior of the Co-57 atomic probe in gold, in which the excess charg e is negative, but the local magnetic moment is unstable, is a consequence of the "impurity stabilization" of the local magnetic moment of the Co-57 a tomic probe. This stabilization arises owing to the interaction of the magn etic moment of the Co-57 atomic probe with the magnetic moment of the conta minating impurity of iron. Comparison of the parameters of segregation of C o-57 atomic probes at the CCR cores in noble metals with the parameters of segregation of Co-57 atomic probes at the CCR cores in tungsten has been pe rformed.