| 1. |
- Kunze, J., et al.
(författare)
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Optical study of competition between ordering and metallicity in La(2-2x)Sr(1+2x)Mn(2)O(7)
- 2003
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 67
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Tidskriftsartikel (refereegranskat)abstract
- We study by spectroscopic ellipsometry the optical in-plane anisotropies in La(2-2x)Sr(1+2x)Mn(2)O(7) with 0.32less than or equal toxless than or equal to0.40 above and below the metal to insulator (MI) transition. Spectral-weight changes in the optical conductivity occur at a cross-over temperature T(’)=280 K for all dopings. Local ordering of orbital and charge degrees of freedom sets in doping dependently at temperatures of 145 Kless than or equal toT(*)less than or equal to310 K. Below the MI transition we observe for all dopings except x=0.36 a vanishing of the charge ordering and an isotropic and metallic state at low frequencies, whereas the local orbital ordering persists. For x=0.36 we observe two different characteristic developments of the ordering processes, one being compatible with the parabolic doping dependence on T(*) established by the other doping levels and the second showing ordering at a temperature slightly above the MI transition. We argue that our observations are compatible with a phase separation scenario.
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| 2. |
- Neuber, G., et al.
(författare)
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Generalized magneto-optical ellipsometry in ferromagnetic metals
- 2004
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 455, s. 39-42
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Tidskriftsartikel (refereegranskat)abstract
- We present spectral generalized magneto-optical ellipsometry as an optical tool to investigate magnetic and electronic properties of ferromagnetic materials. The advantage of the simultaneous observation of the dielectric and the magnetic responses within one measurement procedure is crucial for materials with coupled degrees of freedom near a phase transition or during annealing procedures to improve the film quality by removing grain boundaries. Moreover, we show the implementation of this technique within an UHV-cryostat for a temperature range between 4.2 and 800 K and fields up to 40 mT. Examplary measurements on iron and Permalloy demonstrate the comfortable application of this technique. (C) 2003 Elsevier B.V. All rights reserved.
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| 3. |
- Neuber, G., et al.
(författare)
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Temperature-dependent spectral generalized magneto-optical ellipsometry
- 2003
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Ingår i: Applied Physics Letters. - 0003-6951 .- 1077-3118. ; 83, s. 4509-4511
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Tidskriftsartikel (refereegranskat)abstract
- We present a setup for temperature-dependent spectral generalized magneto-optical ellipsometry (SGME). This technique gives access to the electronic as well as the magnetic properties of ferromagnetic materials within one single magneto-optical measurement. It also allows the determination of the orientation of the magnetization. We show spectra of the real and the imaginary part of the refractive index N as well as the magneto-optical coupling parameter Q of permalloy and iron films for in-plane magnetization. Our findings demonstrate the relevance of SGME for the understanding of the interplay between electronic and magnetic properties of ferromagnetics. (C) 2003 American Institute of Physics.
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