Marlio Bonfim
Centre national de la recherche scientifique
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Publication
Featured researches published by Marlio Bonfim.
Nature Materials | 2011
Ioan Mihai Miron; Thomas Moore; H. Szambolics; L. D. Buda-Prejbeanu; S. Auffret; B. Rodmacq; S. Pizzini; Jan Vogel; Marlio Bonfim; A. Schuhl; Gilles Gaudin
The propagation of magnetic domain walls induced by spin-polarized currents has launched new concepts for memory and logic devices. A wave of studies focusing on permalloy (NiFe) nanowires has found evidence for high domain-wall velocities (100 m s(-1); refs,), but has also exposed the drawbacks of this phenomenon for applications. Often the domain-wall displacements are not reproducible, their depinning from a thermally stable position is difficult and the domain-wall structural instability (Walker breakdown) limits the maximum velocity. Here, we show that the combined action of spin-transfer and spin-orbit torques offers a comprehensive solution to these problems. In an ultrathin Co nanowire, integrated in a trilayer with structural inversion asymmetry (SIA), the high spin-torque efficiency facilitates the depinning and leads to high mobility, while the SIA-mediated Rashba field controlling the domain-wall chirality stabilizes the Bloch domain-wall structure. Thus, the high-mobility regime is extended to higher current densities, allowing domain-wall velocities up to 400 m s(-1).
Applied Physics Letters | 2003
Jan Vogel; W. Kuch; Marlio Bonfim; J. Camarero; Yan Pennec; Francesco Offi; K. Fukumoto; J. Kirschner; A. Fontaine; S. Pizzini
X-ray photoemission electron microscopy (X–PEEM) is a powerful imaging technique that can be used to perform element selective magnetic domain imaging on heterogeneous samples with different magnetic layers, like spin valves and tunnel junctions. We have performed nanosecond time-resolved X–PEEM measurements, on the permalloy layer of a Ni80Fe20 (5 nm)/Cu (10 nm)/Co (5 nm) trilayer deposited on Si(111). We used the pump-probe mode, synchronizing a magnetic pulse from a microcoil with the x-ray photon bunches delivered by the BESSY synchrotron in single bunch mode. Images could be acquired during and after the 20 ns long and 80 Oe high field pulses. The nucleation and subsequent growth of reversed domains in the permalloy could be observed, demonstrating the feasibility of element selective and time-resolved domain imaging using X–PEEM.
Journal of Applied Physics | 2000
K. Mackay; Marlio Bonfim; D. Givord; A. Fontaine
In this article we present a system based on microcoils capable of generating pulsed magnetic fields up to 50 T. We discuss the current generation and the measurement techniques currently used. We have measured the Faraday rotation for different paramagnetic materials, glass, gadolinium gallium garnet, Pr gallium garnet, and Si and have used the results to calibrate the magnetic field achieved. We discuss the relative merits of such a system compared to conventional ones, as well as the field characteristics obtained.
Physical Review Letters | 2006
K. Fukumoto; W. Kuch; Jan Vogel; Fabien Romanens; S. Pizzini; J. Camarero; Marlio Bonfim; J. Kirschner
The dynamics of magnetic domain wall motion in the FeNi layer of a FeNi/Al2O3/Co trilayer has been investigated by a combination of x-ray magnetic circular dichroism, photoelectron emission microscopy, and a stroboscopic pump-probe technique. The nucleation of domains and subsequent expansion by domain wall motion in the FeNi layer during nanosecond-long magnetic field pulses was observed in the viscous regime up to the Walker limit field. We attribute an observed delay of domain expansion to the influence of the domain wall energy that acts against the domain expansion and that plays an important role when domains are small.
Physical Review B | 2005
Fabien Romanens; S. Pizzini; Fabiano Yokaichiya; Marlio Bonfim; Yan Pennec; J. Camarero; Jan Vogel; Jordi Sort; F. Garcia; B. Rodmacq; B. Dieny
Magnetization relaxation of exchange biased (Pt/Co)5/Pt/IrMn multilayers with perpendicular anisotropy was investigated by time-resolved Kerr microscopy. Magnetization reversal occurs by nucleation and domain wall propagation for both descending and ascending applied fields, but a much larger nucleation density is observed for the descending branch, where the field is applied antiparallel to the exchange bias field direction. These results can be explained by taking into account the presence of local inhomogeneities of the exchange bias field.
Physical Review B | 2005
Jan Vogel; W. Kuch; Riccardo Hertel; J. Camarero; K. Fukumoto; Fabien Romanens; S. Pizzini; Marlio Bonfim; F. Petroff; A. Fontaine; J. Kirschner
We have obtained microscopic evidence of the influence of domain wall stray fields on the nanosecond magnetization switching in magnetic trilayer systems. The nucleation barrier initiating the magnetic switching of the soft magnetic
Applied Physics Express | 2009
S. Pizzini; V. Uhlíř; Jan Vogel; Nicolas Rougemaille; Sana Laribi; Vincent Cros; E. Jiménez; J. Camarero; Carsten Tieg; Edgar Bonet; Marlio Bonfim; R. Mattana; C. Deranlot; F. Petroff; C. Ulysse; G. Faini
{\mathrm{Fe}}_{20}{\mathrm{Ni}}_{80}
Journal of Applied Physics | 2004
Jan Vogel; W. Kuch; J. Camarero; K. Fukumoto; Yan Pennec; Marlio Bonfim; S. Pizzini; F. Petroff; A. Fontaine; J. Kirschner
layer in magnetic tunnel junctionlike
IEEE Transactions on Magnetics | 2006
M. Weisheit; Marlio Bonfim; R. Grechishkin; V. Barthem; S. Fähler; D. Givord
\mathrm{FeNi}∕{\mathrm{Al}}_{2}{\mathrm{O}}_{3}∕\mathrm{Co}
Applied Physics Letters | 2004
W. Kuch; Jan Vogel; J. Camarero; K. Fukumoto; Yan Pennec; S. Pizzini; Marlio Bonfim; J. Kirschner
trilayers is considerably lowered by stray fields generated by domain walls present in the hard magnetic Co layer. This internal bias field can significantly increase the local switching speed of the soft layer. The effect is made visible using nanosecond time- and layer-resolved magnetic domain imaging and confirmed by micromagnetic simulations.