GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    57Fe Mössbauer spectroscopy in a diamond-anvil cell at variable high pressures and cryogenic temperatures (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 3787-3792 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A detailed description is given of a new facility for transmission 57Fe Mössbauer spectroscopy (MS) studies on absorbers in a miniature diamond-anvil cell in the temperature range 10–300 K and pressure range 0–45 GPa. Spectra with an adequate signal-to-noise ratio for a reliable analysis to be made have each been measured in 20–30 h of data accumulation time. This has been accomplished in spite of the severe constraints imposed by both the minute sample area and the high attenuation of the 14.4 keV probing radiation by the diamond anvils compared with the experimental conditions of conventional MS experiments. A custom-made Rh(57Co) "point'' source with a high specific activity has been used in conjunction with absorbers that have an optimal enrichment (10%–20%) of 57Fe. The successful implementation of 57Fe Mössbauer spectroscopy at very high pressures and variable cryogenic temperatures has been accomplished by making relatively simple refinements to existing elements of high-pressure MS methodology. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144508
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Compressibility of nanostructured alumina phases determined from synchrotron x-ray diffraction studies at high pressure (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 3280-3285 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Synchrotron x-ray diffraction studies up to pressures of 30 GPa have been performed on both nanostructured γ-Al2O3 and α-Al2O3. The P-V equation of state has been calculated from a fit to the diffraction data to obtain the compressibility for each of the compounds. The bulk modulus B0 of nanostructured γ-Al2O3 having grain-size diameters in the range 4 – 8 nm is B0 =152(8) GPa, appreciably lower than the value B0(approximate)250 GPa of its bulk structural analog. The bulk-modulus of nanophase α-Al2O3 of 25 nm average crystallite diameter, which is difficult to stabilize at smaller dimensions because of thermodynamic considerations, is 252(9) GPa and therefore similar to that of bulk α-Al2O3. These studies suggest that only if the grain-size of alumina is below a critical value of several nanometers can substantial changes be expected in the isothermal bulk modulus compared to that of the isostructural bulk compound. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1394915
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A multipurpose miniature piston-cylinder diamond-anvil cell for pressures beyond 100 GPa (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 1423-1425 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A miniature piston-cylinder diamond-anvil cell (DAC) was constructed and tested for pressure operation at and beyond 100 GPa. Its advantages compared to other piston-cylinder DACs are its compactness (22-mm diam by 21-mm high), self-contained force generator, and simple way of operation. Tungsten carbide backing plates are used for supporting the anvils; one with a hemispherical shape allowing for parallelism alignment, and one with a flat circular shape allowing for lateral alignment of the anvils' culets. The force is generated by six M3 Allen screws and is conveyed to the piston via force rings. Pressures to 130 GPa were achieved with beveled culets having 300-μm flats and Re gaskets. Design features, mode of operation, and performance are described. The latter has been demonstrated for the particular case of Mössbauer spectroscopy in La57FeO3. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148775
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Selected studies of magnetism at high pressure (1996)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 18 (1996), S. 145-161 
    Details
    ISSN: 0392-6737
    Keywords: Metal-insulator transitions ; High-pressure and shock-wave effects in solids ; Mössbauer effect ; other γ-ray spectroscopy ; Transition-metal compounds ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Most previous studies of magnetism in various compounds under extreme conditions have been conducted over a wide pressure range at room temperature or over a wide range of cryogenic temperatures at pressures below 20 GPa (200 kbar). We present some of the most recent studies of magnetism over an extended range of temperatures and pressures far beyond 20 GPa,i.e. in regions of pressure-temperature (P-T) space where magnetism has been largely unexplored. Recent techniques have permitted investigations of magnetism in selected 3d transition metal compounds in regions ofP-T where physical properties may be drastically modified; related effects have often been seen in selected doping studies at ambient pressures. We present57Fe and129I Mössbauer isotope studies covering the range 300–4 K to sub-megabar pressures in compounds such as Sr2FeO4, LaFeO3 and FeI2, representative of a broad class of 3d transition metal compounds. At ambient pressure the electronic structure of the transition metal atom in these antiferromagnetic insulators extends from 3d 4 to 3d 6 and has a distinct influence on the pressure evolution of their magnetic properties. Mössbauer studies of these compounds are considered in conjunction with available structural and electrical transport data at pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02458889
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    High-pressure metallization and electronic-magnetic propertiesof hexagonal cubanite (CuFe2S3) (1997)
    Springer
    Physics and chemistry of minerals 24 (1997), S. 569-573 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract  57Fe Mössbauer studies at room temperature and temperature-dependent resistance studies have been performed on a natural specimen of cubanite (CuFe2S3) in a diamond-anvil cell at pressures up to ∼10 GPa. An insulator-metal phase transition occurs in the range 3.4–5.8 GPa coinciding with a previously observed structural transition from an orthorhombic to a hexagonal NiAs (B8) structure. The room temperature data shows that the metallization process concurs with a gradual transition from a magnetically ordered phase at low pressure to a nonmagnetic or paramagnetic phase at high-pressure. The change in magnetic behaviour at the structural transition may be attributed to a reduction of the Fe-S-Fe superexchange angle formed by edge-sharing octahedra occurring in the high-pressure phase. The non-magnetic or paramagnetic metallic phase at high pressure is retained upon decompression to ambient pressure-temperature conditions, indicative of substantial hysteresis associated with the pressure driven orthorhombic→hexagonal structural transition. The pressure evolution of both the 57Fe Mössbauer hyperfine interaction parameters and resistance behaviour is consistent with the transition from mixed-valence character in the low pressure orthorhombic structure to that of extended-electron delocalization in the hexagonal phase at high-pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002690050074
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Characterization and pH stability of insoluble products of the reaction between cyanide and ferrous sulphate (1992)
    Springer
    Hyperfine interactions 73 (1992), S. 383-386 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract X-ray diffraction (XRD), infrared (IR) spectroscopy and57Fe Mössbauer effect spectroscopy were used to characterize and monitor the pH stability of cyanide and ferrous sulphate reaction mixtures. Limited information was obtained from the XRD and IR measurements because of the amorphous nature of the samples. The Mössbauer studies show that considerable changes occur when there is an increase in pH at which the sample is prepared. Prussian-blue type compounds and iron oxide in the form of small particles crystallize out at low and high pH values, while additional complexes are formed at intermediate pH values of 6 to 9.57Fe Mössbauer effect spectroscopy is thus a powerful technique for monitoring the environmental stability of cyanide waste streams that result when modern methods of extractive metallurgy of gold are employed on mineral ores.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02418613
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The relation betweenT c and anharmonicity in Sn-base A15 superconductors (1992)
    Springer
    Hyperfine interactions 70 (1992), S. 1071-1074 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The absolute value of the recoil-free fraction was measured accurately at three reference temperatures in the range 300 K down to 4 K, in two Sn-baseA 15 superconductors with disparate superconducting properties. The higher-T c compound Nb3Sn (T c≈18K) exhibits low-temperature anharmonicity; this is in contrast to the lattice-dynamics of the low-T c isomorph V3Sn (T c≈4K) in which it is observed that harmonic binding of the Sn atoms is prevalent down to low temperatures. The difference in the superconducting properties of the two compounds is shown to correlate with the considerable difference in their lattice-dynamics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02397514
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    An investigation of the mechanism of detoxification in asbestos (1992)
    Springer
    Hyperfine interactions 73 (1992), S. 377-381 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract 57Fe Mössbauer effect spectroscopy studies were conducted on native crocidolite and on a sample which had been detoxified by means of a chemical treatment with ferric salts. This allows for a comparison between the crystal chemistry of the untreated and treated samples. Significant chemical changes in the treated sample have been inferred from the Fe site-population analysis after conducting a temperature-dependent study of both samples in the range 300 K down to 90 K. These results, together with the results from complementary Electron Spin Resonance (ESR) studies, may help to elucidate the mechanism of toxicity in these asbetiforms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02418612
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    57Fe Mössbauer studies at high pressures and low temperatures (1994)
    Springer
    Hyperfine interactions 92 (1994), S. 1155-1160 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A brief description is given of a new facility that permits57Fe Mössbauer spectroscopy (MS) studies in transmission geometry to be made in the range 10–300 K on absorbers pressurized in a diamond-anvil cell. Examples are given of good quality spectra which have each been obtained in 20–30 hours by using a “point” source of ∼5mCi in conjunction with absorbers that have a comparatively low-enrichment (10–20%) of57Fe. The successful execution of57Fe MS at high pressures and variable cryogenic temperatures has been achieved by making simple refinements to existing elements of high-pressure MS methodology. The facility described herein finds important application in fields of geophysics and condensed matter physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02065748
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Pressure evolution of the EFG and magnetic hyperfine field in the layered antiferromagnet FeI2 (1994)
    Springer
    Hyperfine interactions 90 (1994), S. 447-451 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract When FeI2 is subjected to pressures of up to 20 GPa, a change of approximately 20% occurs in the unit cell volume.57Fe Mössbauer spectroscopy (MS) in a diamondanvil cell has been used to monitor the pressure evolution of the hyperfine interaction parameters of this layered antiferromagnetic insulator. The pressure dependence of the quadrupole splittingQS at 296 K exhibits a maximum at ∼12 GPa and the saturation magnetic hyperfine fieldH 0 increases from 7.4 T at ambient pressure to 12 T at 18 GPa. A qualitative analysis identifies the pressure evolution ofQS with changes in the trigonal component of the crystal field splitting. The pressure variation ofH 0 is attributed to an increase in the average value of the 3d charge density distribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02069154
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...