Superconductivity, magnetism and structural study of some new ternary transition metal borides

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1980

OSTI ID:6306330

Ku, H C

Superconductivy has been found in the rare iridium borides with the general formulae MIr/sub 4/B/sub 4/ and in the pseudoternary (Y/sub x/Lu/sub 1-x/)Ir/sub 4/B/sub 4/systems, where M can be Ho, Er or Tm. The compounds were found to crystallize with the primitive tetragonal CeCo/sub 4/B/sub 4/-type structure and the pure phase in itself is only metastable at best. The close correlation between superconductivity, magnetism and structural metastability is demonstrated with the study of the pseudoternary systems M(Ir/sub x/Rh/sub 1-x/)/sub 4/B/sub 4/(x = 0.25, 0.5 and 0.9) in general, and through the Er(Ir/sub x/Rh/sub 1-x/)/sub 4/B/sub 4/, Ho(Ir/sub x/Rh/sub 1-x/)/sub 4/B/sub 4/ systems, in particular. The boundaries between the paramagnetic, superconducting and magnetically ordered phases in the Ho(Ir/sub x/Rh/sub/1-x/)/sub 4/B/sub 4/ system have been established. The boundaries between the paramagnetic, superconducting and magnetically ordered phases in the Dy(Ir/sub x/Rh/sub 1-x/)/sub 4/B/sub 4/ also have been established. The occurrence of superconductivity with an onset of 7.2 K is reported for the metastable ScRu/sub 4/B/sub 4/ compound, a new member of the body-centered-tetragonal LuRu/sub 4/B/sub 4/-type structure MRu/sub 4/B/sub 4/ systems. Superconducting and crystallographic data for the pseudoternary system (Sc/sub x/Lu/sub 1-x/)Ru/sub 4/B/sub 4/ are also presented and discussed. Three new ternary transition metal boride classes with the CeCo/sub 3/B/sub 2/-type, ErIr/sub 3/B/sub 2/-type and YOs/sub 3/B/sub 4/-type structures are reported with the general formulae: MT/sub 3/B/sub 2/, where T is one of the transition metals Ru, Os, Ru or Ir, and M can be Sc, Y, Th, U or one of the rare earth (RE) elements. Finally, two ternary boride systems with the new LuRuB/sub 2/-type structure are reported. Superconductivity as high as 10.0 K is found for the LuRuB/sub 2/ compound.

• Research Organization: California Univ., San Diego (USA)
• OSTI ID: 6306330
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BORIDES
BORON COMPOUNDS
CRYSTAL STRUCTURE
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EXPERIMENTAL DATA
INFORMATION
IRIDIUM BORIDES
MAGNETISM
NUMERICAL DATA
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS