Kondo effect in systems of reduced dimensionality
Abstract
We have studied the Kondo effect in systems of reduced dimensionality. We find that as any dimension of the system becomes comparable to a critical length, $\ell\sb{c}$, the magnitude of the Kondo contribution to the resistivity is suppressed. This suppression has been observed in both Au(Fe) and Cu(Fe), in crossovers from three to quasi-two dimensions, and in Au(Fe) in a crossover from quasi-two to one dimension. In all cases $\ell\sb{c}\ \sim\ 1500$ A. In related experiments we find that there is an enhancement of the Kondo effect in films of Au(Fe) and Cu(Fe) when a layer of the pure host material is placed on top of the Kondo layer. The enhancement of $\Delta\sb{\rho\kappa}$ is proportional to the thickness of the host layer for $t\sb{host}\ \le$ 500 A. We also report results which demonstrate that, in addition to the effects of the sample size of $\Delta\sb{\rho\kappa}$, the amount of disorder affects $\Delta\sb{\rho\kappa}$. As the disorder of a film is increased, $\Delta\sb{\rho\kappa}$ is suppressed. Finally, we have studied the spin scattering rate $\tau\sbsp{s}{-1}$ as a function of thickness in these Kondo films, and we have found that when the Kondo contribution to the resistivity is suppressed, there is a suppression of $\tau\sbsp{s}{-1}$.
Degree
Ph.D.
Advisors
Giordano, Purdue University.
Subject Area
Condensation
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