New Functions and Novel Materials in RE-Platinum Metal-Boride Systems with Strong Electron Correlation

Strongly correlated electron systems have been one of the most interesting topics in condensed matter science. The key importance in such research is undoubtedly the discovery of unexpected features and revealing the new phases of intermetallics with novel physical behavior and unusual crystal structures. To achieve the goal of discovery of new strongly correlated electron materials displaying superconducting properties and/or heavy fermion phenomena, mixed valent state, different magnetic order, the following classes of intermetallics will be studied: i) Noncentrosymmetric structures: CePt 3 B-, BaAl4 -, CePt 2 B-related, new ternary and high order borides ii) CaCu 5 and related structures. CeCo 3 B2 -type (prototype for superconducting and mixed valence state compound CeRu 3 B2 ) and derivative structures containing this fragment, e.g. Ce2 Ir5 B2 (MgCu 2 - and CeCo 3 B2 - structural intergrowth), Ca3 Rh8 B6 -type structures (parent type for Y3 Os8 B6 , CeCo 3 B2 - and ThCr2 Si 2 - intergrown layered structure), etc., usually displaying a significant contraction of R-R distances. iii) AuCu3 derivative structures: CaTiO3 -, HoCoGa5 -, Li 2 Pt 3 B- related, new layered structures, clustered structures with specific atomic arrangement containing voids of different shape iv) High boron content compounds, AlB2 -type structurally related. Structures with high B content (YCrB4 , Y2 ReB 6 , etc.), containing boron nets, can be regarded as structurally related to AlB2 structure. Substitution of M atoms in AlB2 (prototype of MgB2 superconductor) with those, significantly differentiated by atomic radii, provokes a structural modification of the two-dimensional B-nets composed of B6 -rings in AlB2 in terms of combinations of B5 -, B6 - and B7 -rings. Prospective deliverables of given project on strongly correlated electron functions in rare earth platinum metal borides and related systems concentrated on Ce and Yb (Eu) systems will include: i) Structural and physical properties characteristics of novel materials with strong electron correlation ii) Phase relations in the new Ce,Yb(Eu)-TM-B ternary systems within concentration ranges of compounds formation, given in objectives iii) A complete compilation on the phase equilibria, formation of compounds, crystal structure and physical properties of all ternary compounds (old data as well as data on the novel materials found throughout the proposed project).