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Papers by S. Mangin
Physical Review B, 2012
The spin-torque switching of metallic nanopillar spin valves showing strong perpendicular anisotr... more The spin-torque switching of metallic nanopillar spin valves showing strong perpendicular anisotropy are studied. The magnetic states of the layers depend on extrinsic parameters such as the magnetic field and the dc current applied to the device. A state diagram presents a comprehensive graph of the role of those parameters on the spin-valve magnetic response. After explaining how state diagrams can be built and the different possible representation, experimental state diagrams are studied for perpendicular devices and the influence of lateral size, temperature, and field orientation are shown. An analytical model of a purely uniaxial system is presented. It is shown that this simple model does not properly reflect the experimental results, whereas if the symmetry is broken a qualitative agreement is obtained. Finally, the possible origins of the symmetry break are discussed in light of an analytical model and numerical simulations.
Physical Review B, 2009
The evolution of the magnetic configuration inside an antiferromagnetically coupled GdFe/TbFe bil... more The evolution of the magnetic configuration inside an antiferromagnetically coupled GdFe/TbFe bilayer is studied at room temperature. For such system exchange-bias behaviors have been previously reported and are found to depend on the magnetic configuration above the blocking temperature (∼250 K). Here, the in-plane components of the magnetization are studied for different applied-field orientations. By comparing those results with a one-dimensional micromagnetic model the evolution of the interface magnetic configuration is well described. For the different applied-field orientations the magnetic behavior is found to be dominated by the formation of a magnetic twist at the interface which may adopt one chirality or the other.
Physica B: Condensed Matter, 2000
The European Physical Journal B, 2011
The European Physical Journal B - Condensed Matter, 2003
A study of exchange bias phenomenon in ferrimagnetic /ferromagnetic FeGd/ FeSn bilayers is presen... more A study of exchange bias phenomenon in ferrimagnetic /ferromagnetic FeGd/ FeSn bilayers is presented. The amorphous FeSn and FeGd alloys have been grown by co-evaporation. Specific growth conditions allow to induce an uniaxial anisotropy in both alloys in a parallel direction. After saturation of the bilayers under a positive field, the hysteresis loop of one of the layer is shifted towards a positive field H E. The sign of the exchange bias field H E is shown to be due to the antiferromagnetic coupling between the net magnetizations of both alloys. The field H E is studied as a function of the thickness of each layer and of the temperature. Using ac-susceptibility measurements and polarized neutron reflectometry, it is shown that the reversal of magnetization of the bilayers is dominated by the presence of a domain wall at the interface. This exchange bias system is shown to act as a potential well for the magnetic domain wall. Within this assumption and thanks to a precise magnetic characterization of each alloy, the evolution of H E with the thickness of the layers is well reproduced using simple one-dimensional analytical models for the domain wall or a more elaborate numerical approach.
Applied Physics Letters, 2010
Applied Physics Letters, 2010
APS Bulletin of the American Physical Society. APS March Meeting 2011 Volume 56, Number 1. Monday... more APS Bulletin of the American Physical Society. APS March Meeting 2011 Volume 56, Number 1. MondayFriday, March 2125, 2011; Dallas, Texas. ...
Physical Review B, 2008
We present the magnetization evolution of perpendicular anisotropy TbFe and [Co/Pt] thin films ei... more We present the magnetization evolution of perpendicular anisotropy TbFe and [Co/Pt] thin films either in direct contact resulting in antiferromagnetic interfacial coupling or separated by a thick Pt layer. Magnetometry and x-ray magnetic circular dichroism spectroscopy determine the spatially averaged magnetic properties. Resonant magnetic x-ray small-angle scattering and magnetic soft X-ray transmission microscopy probed the domain configurations and correlations in
Physical Review B, 2012
The spin-torque switching of metallic nanopillar spin valves showing strong perpendicular anisotr... more The spin-torque switching of metallic nanopillar spin valves showing strong perpendicular anisotropy are studied. The magnetic states of the layers depend on extrinsic parameters such as the magnetic field and the dc current applied to the device. A state diagram presents a comprehensive graph of the role of those parameters on the spin-valve magnetic response. After explaining how state diagrams can be built and the different possible representation, experimental state diagrams are studied for perpendicular devices and the influence of lateral size, temperature, and field orientation are shown. An analytical model of a purely uniaxial system is presented. It is shown that this simple model does not properly reflect the experimental results, whereas if the symmetry is broken a qualitative agreement is obtained. Finally, the possible origins of the symmetry break are discussed in light of an analytical model and numerical simulations.
Physical Review B, 2009
The evolution of the magnetic configuration inside an antiferromagnetically coupled GdFe/TbFe bil... more The evolution of the magnetic configuration inside an antiferromagnetically coupled GdFe/TbFe bilayer is studied at room temperature. For such system exchange-bias behaviors have been previously reported and are found to depend on the magnetic configuration above the blocking temperature (∼250 K). Here, the in-plane components of the magnetization are studied for different applied-field orientations. By comparing those results with a one-dimensional micromagnetic model the evolution of the interface magnetic configuration is well described. For the different applied-field orientations the magnetic behavior is found to be dominated by the formation of a magnetic twist at the interface which may adopt one chirality or the other.
Physica B: Condensed Matter, 2000
The European Physical Journal B, 2011
The European Physical Journal B - Condensed Matter, 2003
A study of exchange bias phenomenon in ferrimagnetic /ferromagnetic FeGd/ FeSn bilayers is presen... more A study of exchange bias phenomenon in ferrimagnetic /ferromagnetic FeGd/ FeSn bilayers is presented. The amorphous FeSn and FeGd alloys have been grown by co-evaporation. Specific growth conditions allow to induce an uniaxial anisotropy in both alloys in a parallel direction. After saturation of the bilayers under a positive field, the hysteresis loop of one of the layer is shifted towards a positive field H E. The sign of the exchange bias field H E is shown to be due to the antiferromagnetic coupling between the net magnetizations of both alloys. The field H E is studied as a function of the thickness of each layer and of the temperature. Using ac-susceptibility measurements and polarized neutron reflectometry, it is shown that the reversal of magnetization of the bilayers is dominated by the presence of a domain wall at the interface. This exchange bias system is shown to act as a potential well for the magnetic domain wall. Within this assumption and thanks to a precise magnetic characterization of each alloy, the evolution of H E with the thickness of the layers is well reproduced using simple one-dimensional analytical models for the domain wall or a more elaborate numerical approach.
Applied Physics Letters, 2010
Applied Physics Letters, 2010
APS Bulletin of the American Physical Society. APS March Meeting 2011 Volume 56, Number 1. Monday... more APS Bulletin of the American Physical Society. APS March Meeting 2011 Volume 56, Number 1. MondayFriday, March 2125, 2011; Dallas, Texas. ...
Physical Review B, 2008
We present the magnetization evolution of perpendicular anisotropy TbFe and [Co/Pt] thin films ei... more We present the magnetization evolution of perpendicular anisotropy TbFe and [Co/Pt] thin films either in direct contact resulting in antiferromagnetic interfacial coupling or separated by a thick Pt layer. Magnetometry and x-ray magnetic circular dichroism spectroscopy determine the spatially averaged magnetic properties. Resonant magnetic x-ray small-angle scattering and magnetic soft X-ray transmission microscopy probed the domain configurations and correlations in