63 research outputs found
Anisotropic magneto-Coulomb effect versus spin accumulation in a ferromagnetic single-electron device
We investigate the magneto-transport characteristics of nanospintronics
single-electron devices. The devices consist of single non-magnetic
nano-objects (nanometer size nanoparticles of Al or Cu) connected to Co
ferromagnetic leads. The comparison with simulations allows us attribute the
observed magnetoresistance to either spin accumulation or anisotropic
magneto-Coulomb effect (AMC), two effects with very different origins. The fact
that the two effects are observed in similar samples demonstrates that a
careful analysis of Coulomb blockade and magnetoresistance behaviors is
necessary in order to discriminate them in magnetic single-electron devices. As
a tool for further studies, we propose a simple way to determine if spin
transport or AMC effect dominates from the Coulomb blockade I-V curves of the
spintronics device
Spin injection in a single metallic nanoparticle: a step towards nanospintronics
We have fabricated nanometer sized magnetic tunnel junctions using a new
nanoindentation technique in order to study the transport properties of a
single metallic nanoparticle. Coulomb blockade effects show clear evidence for
single electron tunneling through a single 2.5 nm Au cluster. The observed
magnetoresistance is the signature of spin conservation during the transport
process through a non magnetic cluster.Comment: 3 page
Electric-field control of domain wall nucleation and pinning in a metallic ferromagnet
The electric (E) field control of magnetic properties opens the prospects of
an alternative to magnetic field or electric current activation to control
magnetization. Multilayers with perpendicular magnetic anisotropy (PMA) have
proven to be particularly sensitive to the influence of an E-field due to the
interfacial origin of their anisotropy. In these systems, E-field effects have
been recently applied to assist magnetization switching and control domain wall
(DW) velocity. Here we report on two new applications of the E-field in a
similar material : controlling DW nucleation and stopping DW propagation at the
edge of the electrode
The skyrmion switch: turning magnetic skyrmion bubbles on and off with an electric field
Nanoscale magnetic skyrmions are considered as potential information carriers
for future spintronics memory and logic devices. Such applications will require
the control of their local creation and annihilation, which involves so far
solutions that are either energy consuming or difficult to integrate. Here we
demonstrate the control of skyrmion bubbles nucleation and annihilation using
electric field gating, an easily integrable and potentially energetically
efficient solution. We present a detailed stability diagram of the skyrmion
bubbles in a Pt/Co/oxide trilayer and show that their stability can be
controlled via an applied electric field. An analytical bubble model, with the
Dzyaloshinskii-Moriya interaction imbedded in the domain wall energy, account
for the observed electrical skyrmion switching effect. This allows us to unveil
the origin of the electrical control of skyrmions stability and to show that
both magnetic dipolar interaction and the Dzyaloshinskii-Moriya interaction
play an important role in the skyrmion bubble stabilization
Voltage control of magnetism in ferromagnetic structures (Conference Paper)
San Diego, California, United StatesInternational audienceUntil now, spintronics devices have relied on polarized currents, which still generate relatively high dissipation, particularly for nanodevices based on DW motion. A novel solution to further reduce power consumption is emerging, based on electric field (E) gating to control the magnetic state. Here, we will describe the state of the art and our recent experiments on voltage induced changes in the magnetic properties of ferromagnetic metals. A thorough description of the advances in terms of control of intrinsic properties such as magnetic anisotropy and ferromagnetic transition temperature as well as in intrinsic properties like coercive field and domain wall motion will be presented. Additionally, a section will be dedicated to the summary of the key aspects concerning the fabrication and performance of magneto-electric field-effect devices
Identifying the potential habitat of anchovy Engraulis encrasicolus during different life stages in the Mediterranean Sea
The use of magical plants by curanderos in the Ecuador highlands
Although the use of plants for treating supernaturally caused illnesses (e.g., soul loss, evil wind, witchcraft) has been documented in the Ecuador highlands, so-called magical plants have received much less focused attention than plants used for treating naturalistic disorders. Drawing on interviews done in 2002 and 2003 with 116 curanderos residing in the Ecuador highlands, this paper examines the characteristics of plants identified as magical, how they are used, and how the study of magical plants provides insights into the mindscape of residents of the highlands
Unravelling the role of the interface for spin injection into organic semiconductors
Whereas spintronics brings the spin degree of freedom to electronic devices,
molecular/organic electronics adds the opportunity to play with the chemical
versatility. Here we show how, as a contender to commonly used inorganic
materials, organic/molecular based spintronics devices can exhibit very large
magnetoresistance and lead to tailored spin polarizations. We report on giant
tunnel magnetoresistance of up to 300% in a (La,Sr)MnO3/Alq3/Co nanometer size
magnetic tunnel junction. Moreover, we propose a spin dependent transport model
giving a new understanding of spin injection into organic materials/molecules.
Our findings bring a new insight on how one could tune spin injection by
molecular engineering and paves the way to chemical tailoring of the properties
of spintronics devices.Comment: Original version. Revised version to appear in Nature Physics
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