| 1. |
- Olsen, J. Staun, et al.
(författare)
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High-pressure structural behavior of the double perovskite Sr2CrReO6 : an experimental and theoretical study
- 2009
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Ingår i: High Pressure Research. - : Informa UK Limited. - 0895-7959 .- 1477-2299. ; 29:1, s. 83-86
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Tidskriftsartikel (refereegranskat)abstract
- The high-pressure structural behavior of Sr2CrReO6 has been studied experimentally using synchrotron radiation and the diamond anvil cell and theoretically using density functional theory. The experimental zero-pressure bulk modulus is B0=1704GPa and the pressure derivative is B0'=4.71.0. These results compare well with the calculated values 172.6GPa and 5.7. A pseudo-cubic unit cell can describe the crystal structure at low pressure, but the tetragonal structure becomes evident at high pressure.
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| 2. |
- Davani, Hooman A., et al.
(författare)
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Polarization investigation of a tunable high-speed short-wavelength bulk-micromachined MEMS-VCSEL
- 2012
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819489197 ; 8276, s. Art. no. 82760T-
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Konferensbidrag (refereegranskat)abstract
- We report the investigation of the state of polarization (SOP) of a tunable vertical-cavity surface-emitting laser (VCSEL) operating near 850 nm with a mode-hop free single-mode tuning range of about 12 nm and an amplitude modulation bandwidth of about 5 GHz. In addition, the effect of a sub-wavelength grating on the device and its influence on the polarization stability and polarization switching has been investigated. The VCSEL with an integrated sub-wavelength grating shows a stable SOP with a polarization mode suppression ratio (PMSR) more than 35 dB during the tuning.
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| 3. |
- Krockenberger, Y., et al.
(författare)
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Sr2CrOsO6 : End point of a spin-polarized metal-insulator transition by 5d band filling
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:2, s. 020404-
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Tidskriftsartikel (refereegranskat)abstract
- In the search for new spintronic materials with high spin polarization at room temperature, we have synthesized an osmium-based double perovskite with a Curie temperature of 725 K. Our combined experimental results confirm the existence of a sizable induced magnetic moment at the Os site, supported by band-structure calculations, in agreement with a proposed kinetic-energy-driven mechanism of ferrimagnetism in these compounds. The intriguing property of Sr2 CrOs O6 is that it is at the end point of a metal-insulator transition due to 5d band filling and at the same time ferrimagnetism and high-spin polarization are preserved.
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| 4. |
- Majewski, P., et al.
(författare)
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Magnetic moments of W 5d in Ca2CrWO6 and Sr2CrWO6 double perovskites
- 2005
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 72:13
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the magnetic moment of the W ion in the ferrimagnetic double perovskites Sr2CrWO6 and Ca2CrWO6 by x-ray magnetic circular dichroism at the W L-2,L-3 edges. In both compounds a finite negative spin and positive orbital magnetic moment was detected. The experimental results are in good agreement with band-structure calculations for (Sr/Ca)(2)CrWO6 using the full-potential linear muffin-tin orbital method. It is remarkable that the magnetic ordering temperature, T-C, is correlated with the magnetic moment at the nonmagnetic W atom.
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| 5. |
- Winkler, A., et al.
(författare)
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Magnetism in Re-based ferrimagnetic double perovskites
- 2009
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 11, s. 073047-
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated spin and orbital magnetic moments of the Re 5d ion in the double perovskites A(2)FeReO(6) (A = Ba, Sr, Ca) by x-ray magnetic circular dichroism (XMCD) at the Re L(2,3) edges. In these ferrimagnetic compounds, an unusually large negative spin and positive orbital magnetic moment at the Re atoms was detected. The presence of a finite spin magnetic moment in a 'non-magnetic' double perovskite as observed in the double perovskite Sr(2)ScReO(6) proves that Re has also a small, but finite intrinsic magnetic moment. We further show for the examples of Ba and Ca that the usually neglected alkaline earth ions undoubtedly also contribute to the magnetism in the ferrimagnetic double perovskites.
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