8 research outputs found
Very low 1/f noise at room temperature in fully epitaxial Fe/MgO/Fe magnetic tunnel junctions
We report on room temperature 1/f noise in fully epitaxial
Fe(45nm)/MgO(2.6nm)/Fe(10nm) magnetic tunnel junctions (MTJs) with and without
carbon doping of the Fe/MgO bottom interface. We have found that the normalized
noise (Hooge factor) asymmetry between parallel and antiparallel states may
strongly depend on the applied bias and its polarity. Both types of MTJs
exhibit record low Hooge factors being at least one order of magnitude smaller
than previously reported.Comment: 9 pages, 3 figure
Magnetoresistance through a single molecule
The use of single molecules to design electronic devices is an extremely
challenging and fundamentally different approach to further downsizing
electronic circuits. Two-terminal molecular devices such as diodes were first
predicted [1] and, more recently, measured experimentally [2]. The addition of
a gate then enabled the study of molecular transistors [3-5]. In general terms,
in order to increase data processing capabilities, one may not only consider
the electron's charge but also its spin [6,7]. This concept has been pioneered
in giant magnetoresistance (GMR) junctions that consist of thin metallic films
[8,9]. Spin transport across molecules, i.e. Molecular Spintronics remains,
however, a challenging endeavor. As an important first step in this field, we
have performed an experimental and theoretical study on spin transport across a
molecular GMR junction consisting of two ferromagnetic electrodes bridged by a
single hydrogen phthalocyanine (H2Pc) molecule. We observe that even though
H2Pc in itself is nonmagnetic, incorporating it into a molecular junction can
enhance the magnetoresistance by one order of magnitude to 52%.Comment: To appear in Nature Nanotechnology. Present version is the first
submission to Nature Nanotechnology, from May 18th, 201
Large inverse magnetoresistance in fully epitaxial FeâFe3O4âMgOâCo magnetic tunnel junctions
International audienceFully epitaxial Fe(001)âFe3O4(001)âMgO(001)âCo micron-sized magnetic tunnel junctions have been elaborated on MgO(001) substrates. X-ray reflectivity and high-resolution transmission electron microscopy revealed a good quality and epitaxial growth of the stack with abrupt interfaces. The magnetotransport measurements exhibit a large negative tunneling magnetoresistance (TMR) value for magnetic tunnel junctions including an Fe3O4 layer and a MgO tunnel barrier (â8.5% at 300K and â22% at 80K). Moreover, the sign of the TMR changes with the applied bias. We discuss here the structural quality of the samples and the transport measurement results