Properties of the normal state and superconductivity in the Laves phases of V/sub 2/Hf/sub 1-x/Zr/sub x/

Journal Article · Sat Mar 01 04:00:00 EST 1980 · Sov. Phys. - JETP (Engl. Transl.); (United States)

OSTI ID:6928480

Marchenko, V A; Polovov, V M

The superconductivity transition temperatures T/sub c/, the temperature dependences of the magnetic susceptibility chi, and the heat capacity C/sub p/ of V/sub 2/Hf/sub 1-x/Zr/sub x/ alloys (0< or =x< or =1) are measured. In a narrow concentration range (0.3< or =x< or =0.4) in which T/sub c/ attains its maximum and the structural transition temperature T/sub M/ is minimal, the transition entropy changes drastically from approx.2 J/mole-K (alloys closer to V/sub 2/Hf) to 5.5 J/mole-K (alloys closer to V/sub 2/Zr). This corresponds to a change in the nature of the structural instability. The highest values of chi(T) are attained at temperatures that exceed T/sub M/ somewhat. They are the same for all values of x and are equal to 3.8 x 10/sup -4/ emu/g-atom. On the assumption that the orbital contribution is constant, it is concluded that the effective density of the electron states plays the decisive role in the onset of the structural transition. The low-temperature phase is characterized by a narrow (approx.500 K) minimum in the energy dependence of the state density. An analysis of the high-temperature entropy shows that lattice instability is accompanied by anharmonicity effects that manifest themselves in an appreciable decrease of the geometric mean phonon-spectrum frequency during cooling. It is suggested that the anharmonicity is due to electron contributions to the lattice dynamics.

• Research Organization: Institute of Solid State Physics, USSR Academy of Sciences
• OSTI ID: 6928480
• Journal Information: Sov. Phys. - JETP (Engl. Transl.); (United States), Journal Name: Sov. Phys. - JETP (Engl. Transl.); (United States) Vol. 51:3; ISSN SPHJA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals &amp; Alloys-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
CRYSTAL STRUCTURE
ENERGY-LEVEL DENSITY
ENTROPY
HAFNIUM ALLOYS
INSTABILITY
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
PHONONS
PHYSICAL PROPERTIES
QUASI PARTICLES
SPECIFIC HEAT
SPECTRA
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
VANADIUM ALLOYS
ZIRCONIUM ALLOYS