Spin-Glass Behavior in LaFexCo2-xP2 Solid Solutions: Interplay Between Magnetic Properties and Crystal and Electronic Structures

Journal Article · Sat Jan 01 00:00:00 EST 2011 · Inorganic Chemistry

DOI:https://doi.org/10.1021/ic201328y· OSTI ID:1032479

Kovnir, Kirill ^[1]; Garlea, Vasile O ^[2]; Thompson, Corey ^[1]; Zhou, Haidong ^[1]; Reiff, William ^[1]; Ozarowski, Andrew ^[1]; Shatruk, Michael ^[1]

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1. Florida State University
2. ORNL

To explore the evolution of magnetic properties from ferromagnetic LaCo2P2 to paramagnetic LaFe2P2 (both of ThCr2Si2 structure type) a series of mixed composition LaFexCo2-xP2 (x e 0.5) has been comprehensively investigated by means of single-crystal and powder X-ray and neutron diffraction, magnetization and heat capacity measurements, M ossbauer spectroscopy, and electronic band structure calculations. The Curie temperature decreases from 132 K in LaCo2P2 to 91 K in LaFe0.05Co1.95P2. The ferromagnetic ordering is suppressed at higher Fe content. LaFe0.1Co1.9P2 and LaFe0.2Co1.8P2 demonstrate spin-glass-like behavior, which was also confirmed by the absence of characteristic features of long-range magnetic ordering, namely, a -type anomaly in the heat capacity, a hyperfine splitting in the Mossbauer spectrum, and magnetic reflections in the neutron diffraction pattern. Finally, both LaFe0.3Co1.7P2 and LaFe0.5Co1.5P2 exhibit paramagnetic behavior down to 1.8 K. The unit cell parameters of the mixed compounds do not follow the Vegard behavior as the increase in the Fe content results in the decrease of average M-M distances (M = Fe, Co). Quantum-chemical calculations and crystal orbital Hamiltonian population analysis reveal that upon aliovalent (nonisoelectronic) substitution of Fe for Co the antibonding character of M-M interactions is reduced while the Fermi level is shifted below the DOS peak in the 3d metal subband. As the result, at higher Fe content the Stoner criterion is not satisfied and no magnetic ordering is observed.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1032479
• Journal Information: Inorganic Chemistry, Vol. 50, Issue 20; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CURIE POINT
ELECTRONIC STRUCTURE
FERMI LEVEL
HAMILTONIANS
MAGNETIC PROPERTIES
MAGNETIZATION
NEUTRON DIFFRACTION
SOLID SOLUTIONS
SPECIFIC HEAT
SPECTROSCOPY