Magnetic susceptibility of nanoscale Kondo systems

Authors

Ralph Skomski, University of Nebraska-LincolnFollow
R. Zhang, University of Nebraska, Lincoln
Parashu Kharel, University of Nebraska-LincolnFollow
Axel Enders, University of Nebraska–LincolnFollow
Sy_Hwang Liou, University of Nebraska-LincolnFollow
D. J. Sellmyer, University of Nebraska-LincolnFollow

Date of this Version

2010

Citation

JOURNAL OF APPLIED PHYSICS 107, 09E126 (2010); doi:10.1063/1.3365134

Comments

Copyright 2010 American Institute of Physics

Abstract

The mesoscopic Kondo effect in metallic nanoparticles containing a magnetic impurity is investigated by model calculations. A Maxwell–Garnett approach is used to approximately determine the resistivity of doped nanoparticles in a matrix, and the magnetic susceptibility is estimated from the confinement of the conduction electrons. Conductivity measurements of nanoparticles embedded in a matrix are difficult to realize, because metallic matrices distort the Kondo cloud, whereas insulating or semiconducting matrices yield a very weak signal. By comparison, susceptibility measurements do not suffer from these shortcomings. The Kondo effect survives in nanoparticles even if the cluster size is much smaller than the Kondo screening cloud, but the effective Curie constant becomes constant below a particle-size dependent transition temperature and the temperature dependence of the susceptibility is no longer universal.