Effect of host paramagnetic ions on the Gd{sup 3+} EPR linewidth in diluted Van-Vleck paramagnets Tm{sub {ital x}}Lu{sub 1{minus}{ital x}}PO{sub 4} and Ho{sub {ital x}}Y{sub 1{minus}{ital x}}VO{sub 4} and EPR spectra of Er{sup 3+} in Ho{sub {ital x}}Y{sub 1{minus}{ital x}}VO{sub 4}

Journal Article · Wed May 01 04:00:00 EDT 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.53.11631· OSTI ID:371346

Misra, S K; Andronenko, S I ^[1]

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1. Department of Physics, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec, H3G 1M8 (CANADA)

Gd{sup 3+} EPR linewidths in diluted Van-Vleck paramagnets Ho{sub {ital x}}Y{sub 1{minus}{ital x}}VO{sub 4} ({ital x}=0.0,0.02,0.05,0.1,0.15,0.25,0.3,0.5,0.9,1.0) and Tm{sub {ital x}}Lu{sub 1{minus}{ital x}}PO{sub 4} ({ital x}=0.0,0.1,0.2,0.4,0.6,0.8,1.0) were measured at {ital X} band (8.7{endash}9.6 GHz) in the temperature range 4.2{endash}300 K as functions of temperature and concentration ({ital x}) of the host paramagnetic ions, Ho{sup 3+} and Tm{sup 3+}, respectively. It was found that the dipole-dipole and exchange interactions significantly influenced the measured linewidths in Ho{sub {ital x}}Y{sub 1{minus}{ital x}}VO{sub 4} and Tm{sub {ital x}}Lu{sub 1{minus}{ital x}}PO{sub 4} samples for the concentrations {ital x}{approx_gt}0.1 and {ital x}{approx_gt}0.6, respectively. Further, in Ho{sub {ital x}}Y{sub 1{minus}{ital x}}VO{sub 4} samples with {ital x}{approx_gt}0.3 the EPR lines disappeared at temperatures above 10 K due to the formation of percolation clusters by Ho{sup 3+} ions; the disorder was deduced to have a negligible effect in these hosts. Interaction of the lattice with the electronic quadrupole moment of Ho{sup 3+} ions created different structural sites of Gd{sup 3+} in Ho{sub {ital x}}Y{sub 1{minus}{ital x}}VO{sub 4} samples with {ital x}{approx_gt}0.1 depending on the number of Ho{sup 3+} ions in the immediate neighborhood of a Gd{sup 3+} ion, resulting in the observation of up to three different sets of Gd{sup 3+} EPR spectra. As for Tm{sub {ital x}}Lu{sub 1{minus}{ital x}}PO{sub 4} samples with 0.1{lt}{ital x}{lt}0.8, it was the disorder, rather than a percolation cluster, that dominated the Gd{sup 3+} EPR linewidths due to the rather large difference in the ionic radii of Tm{sup 3+} and Lu{sup 3+} ions, as well as in the unit-cell parameters of TmPO{sub 4} and LuPO{sub 4}. (Abstract Truncated)

• OSTI ID: 371346
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 17 Vol. 53; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ELECTRON SPIN RESONANCE
ELECTRONIC STRUCTURE
ERBIUM IONS
GADOLINIUM IONS
HOLMIUM OXIDES
LUTETIUM PHOSPHATES
MULTICHARGED IONS
PARAMAGNETISM
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
THULIUM PHOSPHATES
VANADIUM OXIDES
YTTRIUM OXIDES