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Abstract CeOs 4 Sb 12 , a member of the skutterudite family, has an unusual semimetallic low-temperature L -phase that inhabits a wedge-like area of the field H —temperature T phase diagram. We have conducted measurements of electrical transport and megahertz conductivity on CeOs 4 Sb 12 single crystals under pressures of up to 3 GPa and in high magnetic fields of up to 41 T to investigate the influence of pressure on the different H – T phase boundaries. While the high-temperature valence transition between the metallic H -phase and the L -phase is shifted to higher T by pressures of the order of 1 GPa, we observed only a marginal suppression of the S -phase that is found below 1 K for pressures of up to 1.91 GPa. High-field quantum oscillations have been observed for pressures up to 3.0 GPa and the Fermi surface of the high-field side of the H -phase is found to show a surprising decrease in size with increasing pressure, implying a change in electronic structure rather than a mere contraction of lattice parameters. We evaluate the field-dependence of the effective masses for different pressures and also reflect on the sample dependence of some of the properties of CeOs 4 Sb 12 which appears to be limited to the low-field region.
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High-Pressure Polymorphism in Silver Ferrite Delafossite, AgFeO 2
The delafossites are a class of layered metal oxides that are notable for being able to exhibit optical transparency alongside an in-plane electrical conductivity, making them promising platforms for the development of transparent conductive oxides. Pressure-induced polymorphism offers a direct method for altering the electrical and optical properties in this class, and although the copper delafossites have been studied extensively under pressure, the silver delafossites remain only partially studied. We report two new high-pressure polymorphs of silver ferrite delafossite, AgFeO2, that are stabilized above ∼6 and ∼14 GPa. In situ X-ray diffraction and vibrational spectroscopy measurements are used to examine the structural changes across the two phase transitions. The high-pressure structure between 6 and 14 GPa is assigned as a monoclinic C2/c structure that is analogous to the high-pressure phase reported for AgGaO2. Nuclear resonant forward scattering reveals no change in the spin state or valence state at the Fe3+ site up to 15.3(5) GPa.
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- Award ID(s):
- 2004474
- PAR ID:
- 10525141
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- Inorganic Chemistry
- Volume:
- 63
- Issue:
- 21
- ISSN:
- 0020-1669
- Page Range / eLocation ID:
- 9763 to 9770
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1021/acs.inorgchem.3c04631
