ArticlePDF Available

Magnetism of F centers: Indication of an antiferromagnetic phase transition in potassium-electro-sodalite

Authors:
Ljiljana Damjanović-Vasilić at University of Belgrade
Ljiljana Damjanović-Vasilić
Galen Stucky at University of California, Santa Barbara
Galen Stucky
VOJISLAV I. SRDANOV
VOJISLAV I. SRDANOV
VOJISLAV I. SRDANOV
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Download full-text PDFDownload full-text PDF
Read full-text
Download citation

Abstract and Figures

Temperature-dependent EPR data of potassium-electro-sodalite (PES), K8[Al6Si6O24](e-)2, are consistent with the occurrence of an antiferromagnetic phase transition at 71±2 K. PES is a Mott insulator which contains an unpaired electron in every sodalite cage. The same transition in sodium-electro-sodalite occurs at a considerably lower temperature (42 K), indicating that the exchange interaction among localized electrons is stronger in PES. PES is obtained by the inclusion of one potassium atom in every cage of potassium sodalite. The 27Al MAS NMR resonance of PES is shifted downfield in respect to diamagnetic potassium-sodalite, K6[Al6Si6O24]. The NMR shift is due to unpaired electrons and is caused by hyperfine Fermi contact interaction.
Figures - uploaded by Ljiljana Damjanović-Vasilić
Author content
All figure content in this area was uploaded by Ljiljana Damjanović-Vasilić
Content may be subject to copyright.
560bb6b208ae914928bd7e
01.pdf
Content uploaded by Ljiljana Damjanović-Vasilić
Author content
All content in this area was uploaded by Ljiljana Damjanović-Vasilić on Sep 30, 2015
Content may be subject to copyright.
Magnetism of F centers: Indication of an antiferromagnetic phase transition in potassium-electro-sodali
te.pdf
Available via license: CC BY-NC-ND 4.0
Content may be subject to copyright.
A preview of the PDF is not available
... At higher loading densities, the s-electrons of nanoclusters demonstrate the intra-cluster interaction within the cage and the inter-cluster interaction through the windows of the cages leading to manifestations of novel electronic properties, 8) such as, ferromagnetic 9,10) and antiferromagnetic [11][12][13][14] orderings and insulator-to-metal (I-M) transitions. 7,[15][16][17] Kclusters in sodalite have shown antiferromagnetic ordering in the Mott insulator phase. ...
... Finally, we compare K n /K 2 -P with K n /K 3 -SOD (K-loaded K-form sodalite). An interesting difference has been observed in the electronic properties, although both GIS and SOD cages have a similar cage size, which results in a similar value of U. In K n /K 3 -SOD at n ≈ 1.0, where n is the average number of guest K atoms per SOD cage (β-cage), an antiferromagnetism (T N ≈ 72 K) has been observed and is assigned to the Mottinsulator at the just half-filled condition with t < U. 12,13) The number density of the localized magnetic moments with the spin 1/2 is ≈ 100% of SOD cages. The eight 6Rs of an SOD cage are shared with the adjacent eight SOD cages, and ar- GIS cage SOD cage (β-cage) Fig. 9. (Color online) Schematic illustrations of K cations at the loading of one guest K-atom (n = 1) into (a) SOD cage (β-cage) of K 3 -SOD and (b) GIS cage of K 2 -P. ...
Insulator-to-Metal Transition in Potassium-Loaded Zeolite P
Article
Full-text available
  • Jan 2015
Potassium metal was loaded into porous crystals of potassium-form maximum aluminum zeolite P (K-MAP), and optical absorption, electrical resistivity, and magnetic susceptibility measurements were performed. The average loading density of potassium atoms per GIS cage of zeolite P, n, was systematically changed up to 1.09. Optical absorption bands are observed around 1.3-2 eV and grow to dominate the spectrum with increasing n. These absorption bands are assigned to the optical excitations of s-electrons confined in the zigzag channels of GIS cages. The temperature dependence of electrical resistivity rho indicates insulating properties for n less than or similar to 1.05. At n = 1.09, rho suddenly decreases by several orders of magnitude, and shows metallic properties indicating that an insulator-to-metal transition occurs between n = 1.05 and 1.09. The samples are basically nonmagnetic at any n. The nonmagnetic and insulating phase at n less than or similar to 1.05 is explained by the formation of small bipolarons in the spin-singlet states. The metallic phase at n = 1.09 is explained by the formation of large polarons.
View
... Alkali metal clusters formed in porous zeolite crystals exhibit a variety of magnetic orders as summarized in Table 1 [1][2][3][4][5][6][7][8][9][10][11][12][13]. There are two main attractive aspects of this system: first, these materials contain no magnetic elements at all, and the magnetic orders are achieved by interactions between the s-electrons of the alkali metals. ...
μ+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu ^+$$\end{document}SR Study on ferromagnetism of Na-K alloy clusters in zeolite low-silica X
Article
Full-text available
  • Feb 2024
  • Hyperfine Interact
Na-K alloy clusters can be formed by loading guest K atoms into the cages of zeolite low-silica X (LSX), which contains both Na+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^+$$\end{document} and K+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^+$$\end{document} ions. Ferromagnetism is known to occur in the insulator phase when the host LSX is relatively Na-rich. In this work, the magnetic properties of this material are studied using positive muon spin rotation/relaxation (μ+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu ^+$$\end{document}SR) technique. The zero-field μ+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu ^+$$\end{document}SR spectra show a significant increase in the relaxation rate below the Curie temperature of about 10 K. The longitudinal field μ+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu ^+$$\end{document}SR spectra at 1.9 K show the decoupling behavior of a static local magnetic field with a broad distribution from a few to several tens of gauss. The magnetic volume fraction is estimated to be higher than 72% from the relaxation amplitude. Thus, the ferromagnetism of this material is intrinsic and not due to impurities. The broad distribution of the local field can be explained by a magnetic model in which not all β\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\beta $$\end{document}-cages of LSX are occupied by the localized moment of the clusters.
View
... The clusters have unpaired electrons and antiferromagnetic order develops when all cages are occupied [3,9,10]. The antiferromagnetic transition temperature (Néel temperature) is about 50 k and 72 k for the Na and k clusters, respectively, and depends on the alkali elemental species [11][12][13][14][15][16]. These materials are justhalf-filled Mott insulators with one electron at each site (cage), and the exchange interaction between s-electrons through the cage window is considered to be the origin of the magnetic order. ...
Antiferromagnetic Orderings of Alkali-metal Nanoclusters Arrayed in Sodalite Crystal Studied by μSR and Other Microscopic Probes
Article
  • Jan 2020
Alkali metal clusters with an unpaired electron can be periodically arranged in a body-centered cubic structure in sodalite, a type of aluminosilicate zeolite, to form a Mott insulator accompanied with an antiferromagnetic ordering. This system does not contain any magnetic elements and is a novel magnetic system in which the magnetic order is realized by alkali metal s-electrons. In order to investigate the origin of the s-electron magnetism in detail, we present examples of studies using muon spin rotation/relaxation (μSR), synchrotron radiation Mössbauer spectroscopy, and neutron diffraction techniques. The spatial expansion of the s-electron wave functions of the nanoclusters with increasing alkali metal content has been directly observed by these experimental methods. This enhances the exchange interaction and increases the transition temperature (Néel temperature). A very simple model material of the Mott-Hubbard system is realized in s-electrons. We also point out that there are great expectations for the future contribution of computer science to this material system, especially to μSR experiments. Fullsize Image
View
... 3) In sodalite and zeolite A structures with relatively small cage sizes (∼7 and ∼11 Å for βand α-cage, respectively) and small sizes of windows between the adjacent cages (∼3 and ∼5 Å), the metallic nature of alkali clusters is strongly suppressed, leading to Mott insulating ground state, for which a variety of magnetic transitions were reported. [6][7][8] On the contrary, larger cage and window sizes (∼13 and ∼8 Å for a supercage) found in low-silica X (LSX) zeolite seem to preserve the metallic nature of alkali clusters when the cages are loaded with sodium. 9) However, sodium loaded LSX zeolite is far from being a simple metal. ...
View
... This system is applied to the study of the magnetism of potassium nano-clusters. Although potassium does not have the dor f -electrons, the magnetic order induced from potassium was reported in the potassium nano-clusters in the cage of the aluminosilicate porus crystal of zeolite, (AlSiO 4 ) 3 , by using several experiments, such as the magnetization measurement, μSR, and 27 Al-NMR [19][20][21][22]. However, they are indirect methods to confirm the potassium-induced magnetization. ...
Synchrotron radiation based Mössbauer absorption spectroscopy of various nuclides
Article
Full-text available
  • Feb 2016
  • Hyperfine Interact
Synchrotron-radiation (SR) based Mössbauer absorption spectroscopy of various nuclides is reviewed. The details of the measuring system and analysis method are described. Especially, the following two advantages of the current system are described: the detection of internal conversion electrons and the close distance between the energy standard scatterer and the detector. Both of these advantages yield the enhancement of the counting rate and reduction of the measuring time. Furthermore, SR-based Mössbauer absorption spectroscopy of 40K, 151Eu, and 174Yb is introduced to show the wide applicability of this method. In addition to these three nuclides, SR-based Mössbauer absorption spectroscopy of 61Ni, 73Ge, 119Sn, 125Te, 127I, 149Sm, and 189Os has been performed. We continue to develop the method to increase available nuclides and to increase its ease of use. The complementary relation between the time-domain method using SR, such as nuclear forward scattering and the energy-domain methods such as SR-based Mössbauer absorption spectroscopy is also noted.
View
Antiferromagnetism and insulator-metal transition of alkali metal-loaded sodalite
Article
  • Apr 2024
  • DALTON T
Magnetic phase diagram of alkali metal-loaded sodalite. The antiferromagnetic transition temperature T N changes systematically with the alkali species of the clusters formed in the cages.
View
Magnetic properties of faujasites
Chapter
  • Jan 2017
This chapter gives data and a brief introduction about the magnetic properties of faujasites.
View
Metal-to-insulator crossover in alkali doped zeolite
Article
Full-text available
  • Jan 2016
We report a systematic nuclear magnetic resonance investigation of the 23Na spin-lattice relaxation rate, 1/T1, in sodium loaded low-silica X (LSX) zeolite, Nan/Na12-LSX, for various loading levels of sodium atoms n across the metal-to-insulator crossover. For high loading levels of n ≥ 14.2, 1/T1T shows nearly temperature-independent behaviour between 10 K and 25 K consistent with the Korringa relaxation mechanism and the metallic ground state. As the loading levels decrease below n ≤ 11.6, the extracted density of states (DOS) at the Fermi level sharply decreases, although a residual DOS at Fermi level is still observed even in the samples that lack the metallic Drude-peak in the optical reflectance. The observed crossover is a result of a complex loading-level dependence of electric potential felt by the electrons confined to zeolite cages, where the electronic correlations and disorder both play an important role.
View
Evolution of the density of states at the Fermi level across the metal-to-insulator crossover in alkali doped zeolite
Article
Full-text available
  • Jun 2015
We report a systematic nuclear magnetic resonance investigation of the $^{23}$Na spin-lattice relaxation rate, $1/T_1$, in sodium loaded low-silica X (LSX) zeolite, Na$_n$/Na$_{12}$-LSX, for various loading levels of sodium atoms $n$ across the metal-to-insulator crossover. For high loading levels of $n \geq 14.2$, $1/T_1T$ shows nearly temperature-independent behavior between 10 K and 25 K consistent with the Korringa relaxation mechanism and metallic ground state. As the loading levels decrease below $n \leq 11.6$, the extracted density of states (DOS) at the Fermi level sharply decreases, although a residual DOS at Fermi level is still observed even in samples that lack the metallic Drude-peak in the optical reflectance. The observed crossover is a result of a complex loading-level dependence of electric potential felt by the electrons confined to zeolite cages, where the electronic correlations and disorder both play an important role.
View
Synchrotron-radiation-based Mössbauer spectroscopy of K 40 in antiferromagnetic potassium nanoclusters in sodalite
Article
  • Apr 2015
Synchrotron-radiation-based M\"ossbauer absorption spectroscopy of $^{40}\mathrm{K}$ nuclei was performed. We investigated potassium nanoclusters arrayed in a porous crystal of sodalite. The nanoclusters exhibit antiferromagnetic (AFM) ordering below $$\simeq${}72$ K. The energy-domain $^{40}\mathrm{K}$ M\"ossbauer spectra were successfully obtained in the temperature range of 8\char21{}140 K. Precise analysis of the spectra indicates the appearance of a hyperfine magnetic field at low temperatures. The hyperfine field was evaluated to be $9.2\ifmmode\pm\else\textpm\fi{}3.0$ T at 8 K. This result signifies the spontaneous polarization of s-electron spins in three-dimensionally arrayed potassium nanoclusters in AFM-ordered states.
View
Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice of F Centers
Article
  • Mar 1998
Evidence for a bcc lattice of F centers in sodium-electro-sodalite (SES), synthesized by exposing dehydrated sodalite to sodium vapor, is presented. A high electron spin density in SES produces isotropic contact shifts in nuclear magnetic resonance (NMR) spectra of the framework nuclei whose magnitude is a discrete function of local electron density. Strong exchange coupling between unpaired electrons gives rise to an antiferromagnetic phase transition in SES at TN = 48+/-2 K, providing the first example of an s-electron antiferromagnet.
View
Na43+ Clusters in sodium sodalite
Article
  • Oct 1992
We have measured and calculated the absorption spectrum of the Na-4(3+) clusters in Na3[AlSiO4]3 sodalite prepared by high-vacuum deposition of sodium atoms. The samples with a Na-4(3+):Na-3(3+) cluster ratio up to 1:10 show a single-absorption feature with lambda(max) = 628 nm (1.99 eV). The absorption originates from the individual sodalite cages containing the Na-4(3+) cluster. For the Na-4(3+):Na-3(3+) cluster ratio larger than 1:10, when some of the Na-4(3+) clusters are likely to interact, the changes in the absorption spectra indicate the onset of insulator-metal transition. Time-dependent quantum mechanical calculations of the photon absorption cross section of Na-4(3+) clusters in sodalite at infinite dilution were carried out. The dependence of the calculated spectra on sodalite framework charges and cluster geometry was used to determine which of the proposed charge distribution models are consistent with the absorption spectra. The best agreement between measurements and calculations is obtained for Na = +1, Si = +1.9, Al = +0.9, and O = -0.95.
View
Interaction of sodium vapour with synthetic sodalite: Sorption and formation of colour centres
Article
  • Oct 1968
  • J PHYS CHEM SOLIDS
A synthetic sodalite hydrate of composition 6(NaAlSiO4)8H2O has been prepared, and subjected to sodium vapour at elevated temperatures after outgassing under high vacuum. Two phases were observed: a violet to black series of non-stoichiometric sorption-complexes having a probable composition 6(NaAlSiO4) x Na where 2 < x ⩽ 4, from which two moles of sodium metal per formula weight could be removed by heating; and a blue complex of probable composition 6(NaAlSiO4) 2Na+.2ϵ− whose colour and magnetic properties have been interpreted in terms of Na43+ paramagnetic centres.
View
  • Jan 1998
  • 2449
  • V I Srdanov
  • G D Strucky
  • E Lippmaa
  • G Engelhardt
V. I. Srdanov, G. D. Strucky, E. Lippmaa, G. Engelhardt, Phys. Rev. Lett. & (1998) 2449
  • Jan 1966
  • 328
  • C J A L Rabo
  • P H Angell
  • V Kasai
  • Schomaker
. J. A. Rabo, C. L. Angell, P. H. Kasai, V. Schomaker, Discuss. Faraday Soc. " (1966) 328
  • Jan 1966
  • 328
  • J A Rabo
  • C L Angell
  • P H Kasai
J. A. Rabo, C. L. Angell, P. H. Kasai, V. Schomaker, Discuss. Faraday Soc. " (1966) 328
  • Jan 1968
  • J PHYS CHEM SOLIDS
  • 1755
  • R M Barrer
  • J F Cole
R. M. Barrer, J. F. Cole, J. Phys. Chem. Solids ' (1968) 1755
  • Jan 1992
  • 9039
  • V I Srdanov
  • K Haug
  • H Metiu
  • G D Strucky
V. I. Srdanov, K. Haug, H. Metiu, G. D. Strucky, J. Phys. Chem. '$ (1992) 9039