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

Abstract

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 DOSmore » 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.« less

Authors:
 [1];  [2];  [1];  [1];  [1];  [1];  [1]
  1. Florida State University
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Flux Isotope Reactor
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1032479
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 50; Journal Issue: 20; Journal ID: ISSN 0020-1669
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CURIE POINT; ELECTRONIC STRUCTURE; FERMI LEVEL; HAMILTONIANS; MAGNETIC PROPERTIES; MAGNETIZATION; NEUTRON DIFFRACTION; SOLID SOLUTIONS; SPECIFIC HEAT; SPECTROSCOPY

Citation Formats

Kovnir, Kirill, Garlea, Vasile O, Thompson, Corey, Zhou, Haidong, Reiff, William, Ozarowski, Andrew, and Shatruk, Michael. Spin-Glass Behavior in LaFexCo2-xP2 Solid Solutions: Interplay Between Magnetic Properties and Crystal and Electronic Structures. United States: N. p., 2011. Web. doi:10.1021/ic201328y.
Kovnir, Kirill, Garlea, Vasile O, Thompson, Corey, Zhou, Haidong, Reiff, William, Ozarowski, Andrew, & Shatruk, Michael. Spin-Glass Behavior in LaFexCo2-xP2 Solid Solutions: Interplay Between Magnetic Properties and Crystal and Electronic Structures. United States. https://doi.org/10.1021/ic201328y
Kovnir, Kirill, Garlea, Vasile O, Thompson, Corey, Zhou, Haidong, Reiff, William, Ozarowski, Andrew, and Shatruk, Michael. Sat . "Spin-Glass Behavior in LaFexCo2-xP2 Solid Solutions: Interplay Between Magnetic Properties and Crystal and Electronic Structures". United States. https://doi.org/10.1021/ic201328y.
@article{osti_1032479,
title = {Spin-Glass Behavior in LaFexCo2-xP2 Solid Solutions: Interplay Between Magnetic Properties and Crystal and Electronic Structures},
author = {Kovnir, Kirill and Garlea, Vasile O and Thompson, Corey and Zhou, Haidong and Reiff, William and Ozarowski, Andrew and Shatruk, Michael},
abstractNote = {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.},
doi = {10.1021/ic201328y},
url = {https://www.osti.gov/biblio/1032479}, journal = {Inorganic Chemistry},
issn = {0020-1669},
number = 20,
volume = 50,
place = {United States},
year = {2011},
month = {1}
}