Magneto-optical Kerr-effect study of the high-field superconductors Eu sub 1 minus x Pb sub x Mo sub 6 S sub 8 and Eu sub 1 minus x Sn sub x Mo sub 6 S sub 8 minus y Se sub y

Journal Article · Thu Aug 01 00:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.2246· OSTI ID:5409937

Fumagalli, P; Schoenes, J ^[1]

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1. Laboratorium fuer Festkoerperphysik, Eidgenoessiche Technische Hochschule Zuerich-Hoenggerberg, CH-8093 Zuerich (Switzerland)

A magneto-optical study on high-field superconductors is presented. We have investigated the four Chevrel-phase compounds PbMo{sub 6}S{sub 8}, EuMo{sub 6}S{sub 8}, Eu{sub 0.5}Pb{sub 0.5}Mo{sub 6}S{sub 8}, and Eu{sub 0.75}Sn{sub 0.25}Mo{sub 6}S{sub 7.6}Se{sub 0.4} in fields up to 120 kOe and temperatures down to 0.5 K. From our optical data we conclude that all these compounds are poor metals with rather few free carriers having effective masses of the order of 10{ital m}{sub {ital e}}. Up to 12 eV, the real part {sigma}{sub 1{ital x}{ital x}} of the optical conductivity is dominated by Mo {ital d}{leftrightarrow}S {ital p} transitions. Agreement is found between {sigma}{sub 1{ital x}{ital x}} and the value of {sigma}{sub 1{ital x}{ital x}}{sup theor} that has been derived from a self-consistent band-structure calculation. In the magneto-optical spectra two dominant Eu{sup 2+} 4{ital f}{r arrow}5{ital d} transitions have been found, a 4{ital f}{r arrow}5{ital de}{sub {ital g}} transition at 2.3 eV and a 4{ital f}{r arrow}5{ital t}{sub 2{ital g}} transition at 3.2 eV. A detailed comparison with the europium monochalcogenides yields a 60% smaller radial overlap integral of the Eu{sup 2+} 4{ital f} and 5{ital d} wave functions in the europium Chevrel phases than in the europium monochalcogenides. A strong deviation from a Brillouin function is found in the Kerr rotation at the energy of the Eu{sup 2+} 4{ital f}{r arrow}5{ital d} transitions as a function of magnetic field at temperatures below 5 K. This deviation is due to another transition, which involves spin-polarized Mo {ital d} states and which we assign to Mo {ital d}{r arrow}S {ital p} transitions by consideration of the line shape and the sign of its magneto-optical contribution.

• OSTI ID: 5409937
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 44:5; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
MOLYBDENUM SULFIDES
KERR EFFECT
SUPERCONDUCTORS
EUROPIUM SULFIDES
LEAD ADDITIONS
MAGNETIC FIELDS
MAGNETO-OPTICAL EFFECTS
QUATERNARY COMPOUNDS
SELENIUM ADDITIONS
SPIN ORIENTATION
STOICHIOMETRY
TIN ADDITIONS
ALLOYS
AMINES
AMMONIUM COMPOUNDS
CHALCOGENIDES
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
EUROPIUM COMPOUNDS
LEAD ALLOYS
MOLYBDENUM COMPOUNDS
ORGANIC COMPOUNDS
ORIENTATION
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
SELENIUM ALLOYS
SULFIDES
SULFUR COMPOUNDS
TIN ALLOYS
TRANSITION ELEMENT COMPOUNDS
360603* - Materials- Properties