Sol-gel synthesis of chromium-doped forsterite

Park, Dong Gon; Burlitch, James M.; Geray, Roland F.; Dieckmann, R.; Barber, Duane B.; Pollock, Clifford R.

doi:10.1021/cm00028a020

Cited by 21 publications

(15 citation statements)

References 1 publication

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“…21 In this method, all the elements are homogeneously mixed at the molecular level, which eliminates the necessity of long-range diffusion. Briefly, the previously published sol-gel synthesis of pure forsterite 22 was modified by introducing chromium as follows.…”

Section: A Crystal Growthmentioning

confidence: 99%

9.6 GHz and 34 GHz electron paramagnetic resonance studies of chromium-doped forsterite

Budil

Park

Burlitch

et al. 1994

The Journal of Chemical Physics

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Photoluminescence and Zeeman effect in chromium-doped 4H and 6H SiCElectron paramagnetic resonance spectroscopy of tetrahedral Cr4+ in chromiumdoped forsterite and åkermanite Chromium-doped forsterite single crystals grown under conditions that produce a high Cr 4 + ICr 3 + ratio were examined by electron paramagnetic resonance (EPR) at 9.6 and 34 GHz. The crystals were grown in 2-3 atm of oxygen by the floating-zone method starting from polycrystalline chromium-doped forsterite powder synthesized via a sol-gel method. Three crystals with chromium concentrations of 110, 300, and 390 ppm were studied. At 34 GHz, transitions are observed for the laser-active tetrahedral Cr 4 + species that are not observable at 9.6 GHz, which improve the resolution and accuracy with which the magnetic parameters can be measured by EPR. In addition, peaks for a non-Kramers species appear at 34 GHz that were not observed at 9.6 GHz. These peaks are not analyzed in detail, but are tentatively ascribed to Cr 4 + inc the octahedral substitution sites of the crystal. At the highest chromium concentration, the C~+ spectra show evidence of direct interaction with Cr4+. A global least-squares fit of the combined 9.6 and 34 GHz data for the 300 ppm crystal gives D=64.26±O.18 GHz, E=-4.619±O.009 GHz, gx=1.955±O.009, gy=2.005 ±0.040, gz= l.965 ±0.006, and places the magnetic z axis in the ab plane at an angle of 43.8±0.3° from the b crystallographic axis (in P bnm ). A method for accurately measuring the Cr 4 +/Cr4+ ratio using EPR line intensities is given. The EPR linewidth of the Cr 4 + center exhibits a strong orientation dependence that is well-modeled by including site variations in the D and E zero-field splittings and in the orientation of the z magnetic axis. The linewidth analysis reveals a high degree of correlation between the distributions in D and E, and a somewhat weaker correlation between E and the z axis orientation. These results are interpreted to suggest that the tetrahedral Cr 4 + sites vary mainly in the degree of compression of the tetrahedral cage along the a crystallographic axis. The Cr 4 + EPR linewidths increase significantly at higher chromium concentration, but maintain the same qualitative orientation dependence. The EPR data indicate that the major contribution to inhomogeneity in the tetrahedral site, which may be related to the tunable range of the Cr 4 + laser center, is distortion induced by chromium substitution into the crystal lattice rather than direct chromium-chromium interactions.

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Section: A Crystal Growthmentioning

confidence: 99%

9.6 GHz and 34 GHz electron paramagnetic resonance studies of chromium-doped forsterite

Budil

Park

Burlitch

et al. 1994

The Journal of Chemical Physics

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“…The detailed description of the crystal growth and characterization was published elsewhere. [10][11][12][13] The Cr:Fo crystal ͑9ϫ4ϫ2 mm 3 ͒ was mounted onto a Supersil quartz holder, with the crystal axis a ͑Pbnm nota-tion͒ parallel ͑by eye͒ with the holder long axis. Rotation of the crystal about its a axis allowed the external magnetic field, B, and the light propagation axis to be aligned in the bc plane.…”

Section: Methodsmentioning

confidence: 99%

Site selective electron paramagnetic resonance study of photoexcited chromium doped forsterite

Regev

Freed

1995

The Journal of Chemical Physics

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Time resolved electron paramagnetic resonance ͑EPR͒ measurements on a photoexcited chromium doped forsterite ͑Cr:Fo͒ single crystal are reported. The spectral changes with time, magnetic field, crystal orientation, microwave power and, in particular, photoexciting wavelength, provide a selective picture of the various chromium dopants and the absorption-relaxation cycle associated with each optical excitation. Both Cr ϩ4 ions lodged at tetrahedral ͑Td͒ and octahedral ͑Oh͒ sites as well as Cr ϩ3 ions are detected. In particular, the laser-EPR technique enabled us to monitor the spin dynamics associated with the lasing center ͑Cr ϩ4 /Td͒ in the time regime of 200 ns-100 ms following a selective photoexcitation of the crystal between 532 and 1064 nm. The transient EPR signals associated with the lasing Cr ϩ4 /Td ions, exhibit a noticeable dependence on even small changes ͑ϳ0.5 nm͒ in the exciting wavelengths that correspond to the visible 3 A 2 → 3 T 1 and the near infrared 3 A 2 → 3 T 2 transitions. The transient magnetization associated with each absorption-relaxation cycle is quantitatively analyzed in terms of site selectivity due to the narrow band ͑i.e., low intensity͒ microwave detection following a narrow band optical excitation. Given this observed selectivity, it is suggested that laser-EPR may be employed to study intersite interactions and site structure versus optical function relationships in forsterite as well as other solids doped with transition metal ions.

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“…W ith the rapid development of optical telecommunication, it is required to improve the transmission capacity of the wavelength division multiplexing (WDM) system. As a result, active ions such as transition metal (Ni and Cr)‐doped optical materials showing ultra‐wide luminescence covering both telecommunication windows, 1.55 μm with the lowest optical attenuation and 1.3 μm with natural zero dispersion for silica fiber, have received great attention in recent years 1–8 . Forsterite, Mg 2 SiO 4 , has an orthorhombic structure with the space group Pbnm and contains four formula units per unit cell.…”

Section: Introductionmentioning

confidence: 99%

“…Untill now, forsterite has been synthesized by sol–gel routes, coprecipitation, and high‐temperature processing techniques 1–9 . Recently, Tani and colleagues prepared crystalline Mg 2 SiO 4 nanopartices of several tens‐of‐nanometer in diameter by flame spray pyrolysis, and they also used them as the luminescent center in organic–inorganic hybrid transparent materials to realize broadband optical amplification 3,5 .…”

Section: Introductionmentioning

confidence: 99%

Molten‐Salt Synthesis and Characterization of Nickel‐Doped Forsterite Nanocrystals

Sun

Fujii

Nitta

et al. 2009

Journal of the American Ceramic Society

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Nickel-doped forsterite (Ni 21 :Mg 2 SiO 4 ) nanocrystals have been synthesized by a facile molten-salt approach in the presence of NaCl and a surfactant (NP-7.5). The products were characterized by X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction (SAED), and luminescence spectra measurements. The crystal size could be controlled by tailoring the synthesis parameters. TEM, high-resolution TEM, and SAED results revealed the single crystalline character of Mg 2 SiO 4 nanoparticles. A possible model for the growth of Ni 21 :Mg 2 SiO 4 nanocrystals was postulated. The obtained Ni 21 :Mg 2 SiO 4 nanocrystals show strong, super broad, near-infrared luminescence at room temperature. These doped Mg 2 SiO 4 nanocrystals are promising gain mediums for super broadband optical amplification.

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Sol-gel synthesis of chromium-doped forsterite

Cited by 21 publications

References 1 publication

9.6 GHz and 34 GHz electron paramagnetic resonance studies of chromium-doped forsterite

9.6 GHz and 34 GHz electron paramagnetic resonance studies of chromium-doped forsterite

Site selective electron paramagnetic resonance study of photoexcited chromium doped forsterite

Molten‐Salt Synthesis and Characterization of Nickel‐Doped Forsterite Nanocrystals

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