Kondo metal

In addition, there are certain metals involving 4f- or 5f-states, formerly called Kondo metals and now described as heavy-fermion materials, which have a very large electronic specific heat and may be described as crystals in which every rare-earth metal is envisaged, coherently, in a Kondo-type spin flip. 

We will proceed as follows. In the first subsection we present the pSR information on Kondo metals, etc., since their behavior is somewhat different from typical HF compounds, which will be discussed in flie next subsection. The sequence used is not based... 

The distinction between Kondo metals, etc. and HF systems is fuzzy at best. As pointed out, the Kondo interaction is, among others, a basic ingredient of HF behavior. In a Kondo-lattice material one observes the effects of the Kondo interaction, for example on the magnetic properties, but very heavy quasiparticles are not formed and in consequence, the Sommerfeld constant is only slightly enhanced, That at least is the basis for a distinction we shall adopt. The hybridization between 4f and conduction electrons can lead to a hybridization gap in the density of states at the Fermi surface. The exact mechanism of gap formation is still under debate and also may vary from compound to compound. If a gap is present, one leaves the realm of Kondo metals and has, depending on the form of the gap (e.g., whether it is open in all crystallographic directions) and on its width, either a Kondo semimetal, semiconductor or insulator. The latter are certainly the most challenging class of Kondo compounds to understand. 

Tp is defined as the temperature when electrons condense into the FL state. If Tp decreases from about 10,000 K, Fermi energy in the normal metal, to the order of 10 K in the Kondo metal, y will grow around 1000 times in value. The effect of pressure will be remarkable as we understand a heavy electron system, which has extremely narrow bandwidth. 

Kondo, T., Uenoyama, S.-y., Fujita, K.-i., and Mitsudo, T.-a., First transition-metal complex catalyzed addition of organic disulfides to alkenes enables the rapid synthesis of vicinal dithioethers, /. Am. Chem. Soc., 121, 482, 1999. 

Yamaguchi M, Kondo I. Immunoelectron microscopy of Proteus vulgaris by the plasma polymerization metal-extraction replica method differential staining of flagellar (H) and somatic (0) antigens by colloidal golds. J Electron Microsc 1989 38 382-388. 

Domen K, Ikeda S, Takata T, Tanaka A, Hara M, Kondo JN (2000) Mechano-catalytic overall water-splitting into hydrogen and oxygen on some metal oxides. Appl Energy 67 159-179... 

Kondo, T., Oyama, K., and Yoshida, K., Chiral molecular recognition on formation of a metalloanthocyanins a supramolecular metal complex pigment from blue flowers of Salvia patens, Angew. Chem. Int. Ed. Engl, 40, 894, 2001. 

Y. Watanabe u. T. Kondo, Novel Organic Syntheses Using Group VIII Metal Complexes, Yuki Gosei... 

The model of a degenerate gas of spin polarons suggests that if the direct or RKKY interaction between moments is weak and EF too great to allow ferromagnetism then the moments might all resonate between their various orientations. This would mean that it is possible in principle to have a heavily doped magnetic semiconductor or rare-earth metal in which there is no magnetic order, even at absolute zero. This possibility is discussed further in Section 8 in connection with the Kondo effect. 

Many papers have been published on the theory of die Kondo effect, including some exact solutions. We recommend the 260 page review by Tsvelich and Weigmann (1983). Our aim in giving a simple non-mathematical account is to point out the similarity between the enhancement of the effective mass that occurs in crystalline metallic systems near to the conditions for a Mott transition (Chapter 4), and also to address the possible effects of free spins in doped semiconductors near the transition (Chapter 5). 

Van Geet has used a similar approach to estimate the chemical shifts of solvated ions (15). He argues that if the repulsive overlap mechanism, shown by Richards et al. (16) to work for ion-ion interactions, also works for ion-solvent interactions, then the repulsive overlap mechanism used by Kondo and Yamashita (17) for alkali metal halide crystals justifies the above assumptions. 

The catalytic activity of TiOz can be increased with the loading of metals such as silver or platinum. The loading of silver onto the surface of Ti02 has been shown to increase the removal of chloroform from 35 to 45% and the removal of urea from 16 to 83% (Kondo and Jardim, 1991). The drawback of this treatment is the dissolution of silver into solution at a level of 0.5 ppm, which is 10 times the regulatory limit (Venkatadri and Peters, 1993). 

---