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Systematic study of mixed valent behavior: resistivity, specific heat, and magnetic susceptibility of Ce(Rh/sub 1-y/Pt/sub y/)/sub 2/ and Ce(Rh/sub 1-x/Ru/sub x/)/sub 2/

Thesis/Dissertation ·
OSTI ID:6344233
The pseudo-binary alloy systems Ce(Rh/sub 1-x/Ru/sub x/)/sub 2/ and Ce(Rh/sub 1-y/Pt/sub y/)/sub 2/ with 0 less than or equal to x, y less than or equal to 1 were studied. The room temperature lattice constant, the electrical resistivity from 1.4 to 300 K (600 K for some samples), the magnetic susceptibility from 2 to 300 K, and the specific heat from 1.1 to 25 k were measured. The same set of measurements were performed on the lanthanum-analog systems, La(Rh/sub 1-x/Ru/sub x/)/sub 2/ and La(Rh/sub 1-y/Pt/sub y/)/sub 2/. The valence of the cerium ions was determined directly using L/sub III/ absorption. The quantities measured indicate that the whole alloying range from CePt/sub 2/ to CeRh/sub 2/ to CeRu/sub 2/ can be separated into two regions: a trivalent region from CePt/sub 2/ to Ce(Rh/sub .5/Pt/sub .5/)/sub 2/ and a mixed valent region from Ce(Rh/sub .5/Pt/sub .5/)/sub 2/ to CeRh/sub 2/ to CeRu/sub 2/. The entire mixed valence range is spanned as the rhodium concentration is varied. CeRh/sub 2/ is mixed valent in agreement with previous results. Parameters calculated from the data are compared to the predictions of two mixed valence theories based on the single impurity degenerate Anderson Hamiltonian, namely the large-N expansion and Bethe-Ansatz methods. The two theories are equivalent and are found in qualitative agreement with the data.
Research Organization:
Temple Univ., Philadelphia, PA (USA)
OSTI ID:
6344233
Country of Publication:
United States
Language:
English