Cr 53 solid-state nuclear magnetic resonance: New observations and comprehensive correlations as a probe of valence and magnetic states
Cr 53 solid-state nuclear magnetic resonance: New observations and comprehensive correlations as a probe of valence and magnetic states
New 53Cr solid-state NMR measurements are presented for Cr2N, CrB2, CrO2, Cr2O3, (NH4)2CrO4, and BaCrO4. Measurements of the 53Cr nuclear quadrupole coupling constants, asymmetry parameters, and chemical (Knight) shifts of chromium compounds provide important experimental data for the validation of quantum chemistry calculations. In this work, natural abundance 53Cr magnetic resonance, at 9.4 T, is used to examine the metals Cr2N and CrB2 as well as the diamagnetic insulating chromates (NH4)2CrO4 and BaCrO4 at room temperature. N14 and B11 NMR spectra are also obtained at room temperature for Cr2N and CrB2, respectively. The shift observed from CrB2 is believed to be the largest Cr(0) Knight shift (-9982 ppm) for any chromium-containing metallic material. 53Cr measurements in zero applied magnetic field as a function of temperature are reported for ferromagnetic CrO2 and antiferromagnetic Cr2O3. Within experimental accuracy the magnetization behavior in CrO2 is modeled using Bloch spin-wave theory, where the magnetization decreases as T3/2 over temperatures from 4.2 to 295 K, which also appears to adequately model the sublattice magnetization of Cr2O3. These new experimental results are put into the context of previous magnetic resonance results found in the literature by providing the first comprehensive tabulation of such 53Cr magnetic resonance data from solids for over 50 years. The low-temperature zero applied magnetic field central frequencies are correlated with valence state, and spin stiffness has been calculated for 16 chromium compounds. A knowledge of these parameters will enable further progress in using 53Cr magnetic resonance as a probe of electronic and magnetic structures, thereby contributing to the more systematic development of novel materials.
Bastow, Timothy J.
971f42ad-72df-444d-89fc-af9d1ec02b66
Hill, Anita J.
19d80ce8-c0ae-4b07-bab2-ece9b0bbe7e2
Nairn, Katherine M.
72058429-337e-44ce-b6b2-7fbb0c508268
Smith, Mark E.
abd04fbf-5f56-459d-89ec-e51ab2598c09
November 2023
Bastow, Timothy J.
971f42ad-72df-444d-89fc-af9d1ec02b66
Hill, Anita J.
19d80ce8-c0ae-4b07-bab2-ece9b0bbe7e2
Nairn, Katherine M.
72058429-337e-44ce-b6b2-7fbb0c508268
Smith, Mark E.
abd04fbf-5f56-459d-89ec-e51ab2598c09
Bastow, Timothy J., Hill, Anita J., Nairn, Katherine M. and Smith, Mark E.
(2023)
Cr 53 solid-state nuclear magnetic resonance: New observations and comprehensive correlations as a probe of valence and magnetic states.
Physical Review Materials, 7 (11), [114410].
(doi:10.1103/PhysRevMaterials.7.114410).
Abstract
New 53Cr solid-state NMR measurements are presented for Cr2N, CrB2, CrO2, Cr2O3, (NH4)2CrO4, and BaCrO4. Measurements of the 53Cr nuclear quadrupole coupling constants, asymmetry parameters, and chemical (Knight) shifts of chromium compounds provide important experimental data for the validation of quantum chemistry calculations. In this work, natural abundance 53Cr magnetic resonance, at 9.4 T, is used to examine the metals Cr2N and CrB2 as well as the diamagnetic insulating chromates (NH4)2CrO4 and BaCrO4 at room temperature. N14 and B11 NMR spectra are also obtained at room temperature for Cr2N and CrB2, respectively. The shift observed from CrB2 is believed to be the largest Cr(0) Knight shift (-9982 ppm) for any chromium-containing metallic material. 53Cr measurements in zero applied magnetic field as a function of temperature are reported for ferromagnetic CrO2 and antiferromagnetic Cr2O3. Within experimental accuracy the magnetization behavior in CrO2 is modeled using Bloch spin-wave theory, where the magnetization decreases as T3/2 over temperatures from 4.2 to 295 K, which also appears to adequately model the sublattice magnetization of Cr2O3. These new experimental results are put into the context of previous magnetic resonance results found in the literature by providing the first comprehensive tabulation of such 53Cr magnetic resonance data from solids for over 50 years. The low-temperature zero applied magnetic field central frequencies are correlated with valence state, and spin stiffness has been calculated for 16 chromium compounds. A knowledge of these parameters will enable further progress in using 53Cr magnetic resonance as a probe of electronic and magnetic structures, thereby contributing to the more systematic development of novel materials.
Text
53Cr Original Submission_Revised July 27 PRM re-submission Accepted
- Accepted Manuscript
More information
Accepted/In Press date: 27 September 2023
e-pub ahead of print date: 27 November 2023
Published date: November 2023
Additional Information:
Publisher Copyright:
© 2023 American Physical Society. AU.
Identifiers
Local EPrints ID: 486414
URI: http://eprints.soton.ac.uk/id/eprint/486414
ISSN: 2475-9953
PURE UUID: 123a15b5-f401-4450-8169-202fb3da3bdf
Catalogue record
Date deposited: 19 Jan 2024 18:49
Last modified: 17 Apr 2024 16:48
Export record
Altmetrics
Contributors
Author:
Timothy J. Bastow
Author:
Anita J. Hill
Author:
Katherine M. Nairn
Author:
Mark E. Smith
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics