Electron spin resonance of paramagnetic impurities in antiferromagnetic compounds

The possibility of magnetic resonance measurements on an impurity in an antiferromagnetic host lattice is discussed. The ion is subject to an internal field B int ; consisting of B dip , the dipolar field generated by the antiferromagnetic moments of the host ions, that can be calculated, and an exchange field B E . For a simple two sublattice antiferromagnet, two resonance frequencies should be observed; equations for their angular dependence are given, including the effect of hyperfine interaction. Impurity ions with Kramers doublets are discussed, together with ions with singlet ground states, for which enhanced nuclear resonance should be possible. A number of simple antiferromagnetic compounds of lanthanide (4f) ions that order at liquid helium temperatures are mentioned briefly, but for simplicity, the discussion is concentrated on GdVO 4 as the host lattice. A formula, based on the known exchange field in the host lattice, is deduced for its effect on the impurity ion.

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Magnetic resonance of lanthanide ions as magnetic probes in the antiferromagnetic phase of dysprosium phosphate

Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences ◽

10.1098/rspa.1991.0164 ◽

1991 ◽

Vol 435 (1895) ◽

pp. 605-614 ◽

Cited By ~ 7

Keyword(s):

Magnetic Resonance ◽

Magnetic Moments ◽

Internal Field ◽

Host Lattice ◽

Lanthanide Ions ◽

Exchange Field ◽

Impurity Ions ◽

Isotropic Exchange ◽

Impurity Ion ◽

Magnetic Probes

Measurements of electron magnetic resonance are discussed for impurity ions in the antiferromagnetic host compound DyPO 4 (Néel temperature T N = 3.39 K). This is a simple two sublattice antiferromagnet; the impurity ions are Yb 3+ and Er 3+ , each with a Kramers doublet as the ground state. Resonance is observed at frequencies of ca . 24 and 34 GHz, and the angular dependence of the magnetic field is fitted to simple theoretical equations. Since the magnetic moments in the host lattice are ordered, the resonance lines are relatively narrow, making it possible to determine the value of the internal field acting on each impurity ion. From this, the exchange field is obtained by subtracting the value of the dipolar field generated by the ordered moments of the host ions. Some measurements have been made in the spin flop phase. The values of the exchange field are found not to conform to a simple model based on isotropic exchange interaction between the real electron spins of the lanthanide ions. Hyperfine splitting is detected from the odd isotope 171 Yb, natural abundance 14%, I = ½.

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A study of the host lattice effect in the lanthanide hydroxides. 34 GHz Gd3+ impurity ion EPR spectra at 77 and 294 K

Canadian Journal of Physics ◽

10.1139/p82-212 ◽

1982 ◽

Vol 60 (11) ◽

pp. 1573-1588 ◽

Cited By ~ 18

Author(s):

V. M. Malhotra ◽

H. A. Buckmaster

Keyword(s):

Point Charge ◽

Ionic Radius ◽

Host Lattice ◽

Epr Spectra ◽

Zero Field ◽

Nearest Neighbour ◽

Zero Field Splitting ◽

Impurity Ions ◽

Lattice Effect ◽

Impurity Ion

The 34 GHz EPR spectra of 5-state (4f7, 8S) Gd3+ impurity ions (~1%) in the isostructural [Formula: see text] symmetry Ln(OH)3 host lattice (Ln ≡ La, Sm, Eu, Tb, Ho, Y) have been studied at 77 and 294 K. The expected seven line ΔM = ± 1 spectrum is observed for Ln = La, Eu, Ho, and Y whereas only a single broad transition is observed for Ln ≡ Sm and Tb. The observed values of the zero field splitting (ZFS) parameter B20 as well as the TZFS are found to be related linearly to (i) the ionic radius, (ii) the Ln–O1 distance, and (iii) the Ln–O2 distance where O1 and O2 are the nearest neighbour equatorial and apical oxygens. However, the slopes are opposite to that predicted by a point charge lattice model. This paper discusses (i) the SH parameters, (ii) the host lattice effect, (iii) the ZFS processes, and (iv) the linewidths observed in the Ln(OH)3 host lattice and attempts to explain the observations using the existing theory. It is found that this apparently simple host lattice exhibits complex effects which do not change systematically with the host lanthanide ion, unlike that observed in most other isostructural lanthanide hosts that have been studied using Gd3+ impurity ions.

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Temperature dependence of nuclear resonance frequencies in the two-dimensional ferromagnet K2CuF4

Physics Letters A ◽

10.1016/0375-9601(73)90535-5 ◽

1973 ◽

Vol 43 (1) ◽

pp. 39-41 ◽

Cited By ~ 10

Author(s):

Le Dang Khoi ◽

P. Veillet ◽

J-P. Renard ◽

C. Jacoboni

Keyword(s):

Temperature Dependence ◽

Nuclear Resonance ◽

Two Dimensional ◽

Resonance Frequencies

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Electron-spin-resonance determination of the internal field within the superconductorYBa2Cu3O7

Physical Review B ◽

10.1103/physrevb.41.2046 ◽

1990 ◽

Vol 41 (4) ◽

pp. 2046-2048 ◽

Cited By ~ 10

Author(s):

Horacio A. Farach ◽

Eduardo Quagliata ◽

Taha Mzoughi ◽

Manuel A. Mesa ◽

Charles P. Poole ◽

...

Keyword(s):

Electron Spin Resonance ◽

Electron Spin ◽

Internal Field ◽

Spin Resonance

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Using Hyperfine Interaction for the Structural Characterization of Amorphous Silicon

MRS Proceedings ◽

10.1557/proc-69-397 ◽

1986 ◽

Vol 69 ◽

Author(s):

Martin Stutzmann ◽

David K. Biegelsen

Keyword(s):

Hyperfine Interaction ◽

Amorphous Silicon ◽

Dipolar Coupling ◽

Double Resonance ◽

Nuclear Spins ◽

Electron Nuclear Double Resonance ◽

Resonance Frequencies ◽

Spin Resonance ◽

Nuclear Spin System

AbstractThe hyperfine interaction between electronic and nuclear spins in hydrogenated amorphous silicon has been observed for the various paramagnetic defects in this material by electron spin resonance (ESR) and electron nuclear double resonance (ENDOR). The large hyperfine interaction between dangling bonds and 29Si as well as between donor electrons and 31p or 75 As nuclei can be resolved in ESR and provides direct information about the structure of the underlying electronic states. The smaller dipolar coupling of all paramagnetic states to more distant nuclei leads to an ENDOR response near the free nuclear resonance frequencies, which can be used to study the coupling of the electronic and nuclear spin system to the lattice phonons and to each other.

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Microscopic Study of Metal Hydrides using Electron Spin resonance

MRS Proceedings ◽

10.1557/proc-3-321 ◽

1980 ◽

Vol 3 ◽

Author(s):

E. L. Venturini

Keyword(s):

Electron Spin Resonance ◽

Electron Spin ◽

Metal Hydrides ◽

Esr Spectra ◽

Spectroscopic Technique ◽

Host Lattice ◽

Hydrogen Ions ◽

Spin Resonance ◽

Symmetry Phase ◽

Paramagnetic Ions

ABSTRACTElectron spin resonance (ESR) of dilute paramagnetic ions in nonmagnetic metallic hydrides provides microscopic information about the hydrogen ions in the immediate vicinity of the impurity. By comparing ESR spectra for different host metals and several hydrogen/metal ratios, one can determine material properties including host lattice symmetry, phase boundaries and occupation of available sites by hydrogen. Examples are presented of ESR of dilute Er in group IIIB and IVB metal hydrides, demonstrating the sensitivity and versatility of ESR as a spectroscopic technique.

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Apparatus for nuclear electron double resonance at 12500 gauss

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1964.0117 ◽

1964 ◽

Vol 279 (1379) ◽

pp. 474-480 ◽

Cited By ~ 12

Keyword(s):

Double Resonance ◽

Resolving Power ◽

Microwave Cavity ◽

Microwave Circuit ◽

Nuclear Resonance ◽

Radio Frequency Coil ◽

Polar Solvents ◽

Resonance Frequencies ◽

Better Than ◽

Double Resonances

Apparatus is described for measuring nuclear electron double resonances a t magnetic fields of 12500 G, in the microwave radiation of about 35000 Mc/s and at nuclear resonance frequencies from 3 to 60 Mc/s. The microwave circuit permits saturation of solutions of certain organic free radicals in solution in non-polar solvents when placed in a microwave cavity with a radio-frequency coil mounted inside. The resolving power of the nuclear resonance spectrometer is better than 1 in 10 8 . Recordings are presented to illustrate the performance of the apparatus.

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Paramagnetic resonance and optical absorption of trapped holes and electrons in irradiated KCI: Ag

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1963.0016 ◽

1963 ◽

Vol 271 (1345) ◽

pp. 243-267 ◽

Cited By ~ 130

Keyword(s):

Electron Spin Resonance ◽

Low Temperature ◽

Optical Absorption ◽

Electron Spin ◽

Optical Absorption Spectra ◽

Paramagnetic Resonance ◽

Spin Resonance ◽

Impurity Ions ◽

Temperature Irradiation ◽

Positive Holes

The electron spin resonance and optical absorption spectra of crystals of KCl containing silver impurity ions were examined after the crystals had been X -irradiated at 77 °K. It is shown that the silver impurity ions act as traps for both electrons and positive holes. A description is given of the annealing behaviour of the crystals after low-temperature irradiation.

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Evidence for internal field in graphite: a conduction electron spin-resonance study

Solid State Communications ◽

10.1016/s0038-1098(01)00465-3 ◽

2002 ◽

Vol 121 (9-10) ◽

pp. 579-583 ◽

Cited By ~ 40

Author(s):

M.S Sercheli ◽

Y Kopelevich ◽

R Ricardo da Silva ◽

J.H.S Torres ◽

C Rettori

Keyword(s):

Electron Spin Resonance ◽

Electron Spin ◽

Conduction Electron ◽

Internal Field ◽

Electron Spin Resonance Study ◽

Spin Resonance ◽

Spin Resonance Study

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EPR-Einkristall-Untersuchungen an (n-Bu4N)2[Cu(dmit)2] im antiferromagnetisch gekoppelten Wirtsgitter (n-Bu4N)2[(dmit)Cu(tto)Cu(dmit)]: Ein Beitrag zur Aufklärung der sogenannten „paramagnetischen Verunreinigung“ im Wirtsgitter / A Single Crystal EPR Investigation on (n-Bu4N)2[Cu(dmit)2] in the Antiferromagnetically Coupled Host Lattice (n-Bu4N)2[(dmit)Cu(tto)Cu(dmit)]: A Contribution to the Nature of the So-called “Paramagnetic Impurities”

Zeitschrift für Naturforschung B ◽

10.1515/znb-1999-0702 ◽

1999 ◽

Vol 54 (7) ◽

pp. 832-838 ◽

Cited By ~ 2

Author(s):

Grit Teschmit ◽

P. Strauch ◽

A. Barthel ◽

J. Reinhold ◽

R. Kirmse

Keyword(s):

Density Functional Theory ◽

Single Crystal ◽

Structure Data ◽

Copper Complex ◽

Density Functional ◽

Host Lattice ◽

Mo Calculations ◽

Functional Theory ◽

Paramagnetic Impurities ◽

Hückel Theory

Single-crystal EPR investigations on the paramagnetic CuII impurity present in the binuclear antiferromagnetically coupled complex (n-Bu4N)2[(dmit)CuII(tto)CuII,(dmit)] (dmit = dimercaptoisotrithion, tto = tetrathiooxalate) identify the mononuclear S =½ complex [CuII(dmit)2]2− as being responsible for the observed EPR spectra. The 63Cu hyperfine structure data as well as the data obtained from density functional theory (DFT) and extended Hückel theory molecular orbital (EHT-MO) calculations were used to characterize the spin-density distribution of the copper complex.

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