Electron paramagnetic resonance and ENDOR studies of Cr3+ - Al3+ pairs in forsterite

Bershov, L. V.; Gaite, J. M.; Hafner, S. S.; Rager, H.

doi:10.1007/bf00308364

Cited by 41 publications

(25 citation statements)

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“…In the second layer the occupied chain lies directly above the unoccupied chain of the first layer, and is related to the occupied chain of the first layer by the b glide plane. It was established previously that Cr" ions may substitute Mg" in the octahedrally coordinated Ml and M2 positions with nonlocal charge compensation [7,9,10], and Cr` substitutes Si" in the tetrahedral position [11][12][13][14]. Our investigations showed that chromium may substitute Mg" in M1 and M2 positions as a divalent cation [15].…”

Section: Introductionmentioning

confidence: 97%

“…This crystal was previously studied as one of widely occurring minerals [3][4][5][6][7][8][9][10]. The chemical formula of forsterite is Mg 2 SiO4.…”

Section: Introductionmentioning

confidence: 99%

“…Dimer centers Cri -Al" with Cr" ions substituting Mg" in M1 and M2 positions, and Al" substituting Si" in the tetrahedral position closest to Cr", were also observed. It was established that the concentration of the dimer centers Cr'+-Al 3 + considerably exceeded the statistical concentration for a given concentration of Cr" and Al" ions [10].…”

Section: Introductionmentioning

confidence: 99%

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High-frequency tunable EPR spectroscopy of Cr3+ in synthetic forsterite

Shakurov

Tarasov

2001

Appl. Magn. Reson.

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The electron paramagnetic resonance spectra of isolated and dimer impurity centers of trivalent chromium ions in the octahedral M1 sites in synthetic forsterite are studied in the frequency range of 65-90 GHz. The measurements are performed at 4.2 K in magnetic. field from -0.04 to 0.3 T. The zero-field splitting between spin doublets of the isolated Cr" ion A s = 66.7 GHz and between spin sublevels of the Cr-Cr" dimer A d! = 71.5 GHz and Ade = 73.0 GHz is measured directly at zero field. The analysis of the spin Hamiltonian parameters shows that the dimer center consists of a pair of Cr' ions with an Mgt vacancy between them replacing three Mgt ions situated in a quasi-one-dimensional chain aligned parallel to the crystal c-axis. It is found that the exchange interaction in the dimer is ferromagnetic with parameters J = 0.47 GHz and J, = 0.79 GHz.

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Section: Introductionmentioning

confidence: 97%

“…This crystal was previously studied as one of widely occurring minerals [3][4][5][6][7][8][9][10]. The chemical formula of forsterite is Mg 2 SiO4.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-frequency tunable EPR spectroscopy of Cr3+ in synthetic forsterite

Shakurov

Tarasov

2001

Appl. Magn. Reson.

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“…There were observed, in particular, the associates formed by two Cr 3+ ions in the M1 sites with a Mg 2+ vacancy between them instead of three adjacent Mg 2+ ions located in the above mentioned quasi-one-dimensional chain of magnesium positions MI in forsterite [16]. ions in the MI or M2 sites, and A13+ in the tetrahedral site, the nearest one to the impurity Cr 3+ [17]. Forsterite co-doped by Cr 3+ and Li + possesses a high concentration of Cr3 § + associates [18], where Cr 3+ ions substitute for Mg 2+ in the M1 and M2 sites and Li + substitute Mg -'+ in the neighboring M2 or M1 site.…”

Section: Introductionmentioning

confidence: 99%

Multifrequency EPR spectroscopy of Ho3+ ions in synthetic forsterite

et al. 2005

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Electron paramagnetic resonance (EPR) of |1o 3 § single ions and llo3'-Mg-"-vacancy-llo 3' associates in holmium-doped forsterite single crystals are studied at 9.4, 37.3 and 65-250 Gtlz. Crystals were grown from melt by the Czochralski technique in slightly oxidizing atmosphere. For both centers, directions of the principal magnetic axes and parameters of the effective spin Hamiltonians describing dependences of electron-nuclear levels on applied magnetic field are obtained. For [lo s' substituting Mg"" in the M2 site as the single ion and for Ho "~" ions in dimer centers, values of crystal field parameters related to a real crystal lattice structure are estimated in the framework of the exchange charge model. The calculated crystal field energies, values of the g-factors of the ground I-[o 3~ quasi-doublet and the directions of the corresponding magnetic moments agree satisfactorily with the data obtained from measurements of EPR and optical absorption and site-selective luminescence spectra. I IntroductionForsterite (Mg2SO4) is a member of family of olivines (Mg.~ej_x)2SiO 4, one of the widespread rock-forming minerals. Nowadays the interest to forsterite single crystals is related also with the efficient tunable laser oscillation of chromiumdoped forsterite, obtained to the moment in different regimes, including continious-wave oscillation [1, 2] and femtosecond pulse generation [3].A unir cell of forsterite crystalline structure (the lattice constants equal a = 0.4753, b = 1.019, c = 0.5988 nm) contains 4 formula units and has an orthorhombic symmetry with a space group Pbnm. The idealized olivine structure consists of a hexagonal close-packed array of oxygen anions, between which the octahedral and tetralaedral holes are located. One hall of those octahedral holes are occupied by Mg -'+ cations and 1/4 of tetrahedral holes are occupied

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“…Beside the EPR pattern for Cr 3 § at the Mg sites, M1 and M2, in forsterite (Bershov et al 1983) very small amounts of Fe 3+ and Mn 2 § were detected. From the intensity of the Cr 3 § EPR transitions follows that Cr 3+ is approximately equally partioned between MI and M2.…”

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confidence: 95%

Polarized optical absorption spectra of synthetic chromium doped Mg2SiO4 (forsterite)

Rager

Taran²,

Khomenko³

1991

Phys Chem Minerals

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Abstract. Polarized optical absorption measurements were carried out on three single crystals of Mg2SiO 4 (forsterite), differently doped with Cr. Two crystals containing average 0.013 and 0.027 weight% Cr, respectively, were pulled from the melt in air, whereas one crystal containing average 0.08 weight% Cr was pulled from the melt in an argon atmosphere. The absorption spectra of the three crystals agree with each other although the intensity of single absorption bands varies significantly. In all 7-polarized patterns a sharp absorption line around 18 000 cm-x (550 rim) appears. Conjectures are presented to assign this line to the lasing center in Cr doped forsterite which very likely exists as Cr a+ at the fourfold coordinated Si site.

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Electron paramagnetic resonance and ENDOR studies of Cr3+ - Al3+ pairs in forsterite

Cited by 41 publications

References 11 publications

High-frequency tunable EPR spectroscopy of Cr3+ in synthetic forsterite

High-frequency tunable EPR spectroscopy of Cr3+ in synthetic forsterite

Multifrequency EPR spectroscopy of Ho3+ ions in synthetic forsterite

Polarized optical absorption spectra of synthetic chromium doped Mg2SiO4 (forsterite)

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