31 research outputs found
Readout of a antiferromagnetic spintronics systems by strong exchange coupling of Mn2Au and Permalloy
In antiferromagnetic spintronics, the read-out of the staggered magnetization
or Neel vector is the key obstacle to harnessing the ultra-fast dynamics and
stability of antiferromagnets for novel devices. Here, we demonstrate strong
exchange coupling of Mn2Au, a unique metallic antiferromagnet that exhibits
Neel spin-orbit torques, with thin ferromagnetic Permalloy layers. This allows
us to benefit from the well-estabished read-out methods of ferromagnets, while
the essential advantages of antiferromagnetic spintronics are retained. We show
one-to-one imprinting of the antiferromagnetic on the ferromagnetic domain
pattern. Conversely, alignment of the Permalloy magnetization reorients the
Mn2Au Neel vector, an effect, which can be restricted to large magnetic fields
by tuning the ferromagnetic layer thickness. To understand the origin of the
strong coupling, we carry out high resolution electron microscopy imaging and
we find that our growth yields an interface with a well-defined morphology that
leads to the strong exchange coupling.Comment: 9 pages, 5 figure
The composition of the protosolar disk and the formation conditions for comets
Conditions in the protosolar nebula have left their mark in the composition
of cometary volatiles, thought to be some of the most pristine material in the
solar system. Cometary compositions represent the end point of processing that
began in the parent molecular cloud core and continued through the collapse of
that core to form the protosun and the solar nebula, and finally during the
evolution of the solar nebula itself as the cometary bodies were accreting.
Disentangling the effects of the various epochs on the final composition of a
comet is complicated. But comets are not the only source of information about
the solar nebula. Protostellar disks around young stars similar to the protosun
provide a way of investigating the evolution of disks similar to the solar
nebula while they are in the process of evolving to form their own solar
systems. In this way we can learn about the physical and chemical conditions
under which comets formed, and about the types of dynamical processing that
shaped the solar system we see today.
This paper summarizes some recent contributions to our understanding of both
cometary volatiles and the composition, structure and evolution of protostellar
disks.Comment: To appear in Space Science Reviews. The final publication is
available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-
No evidence of brown adipose tissue activation after 24 weeks of supervised exercise training in young sedentary adults in the ACTIBATE randomized controlled trial
Exercise modulates both brown adipose tissue (BAT)metabolismand white
adipose tissue (WAT) browning in murine models. Whether this is true in
humans, however, has remained unknown. An unblinded randomized controlled
trial (ClinicalTrials.gov ID: NCT02365129) was therefore conducted to
study the effects of a 24-week supervised exercise intervention, combining
endurance and resistance training, on BAT volume and activity (primary outcome).
The study was carried out in the Sport and Health University Research
Institute and the Virgen de las Nieves University Hospital of the University of
Granada (Spain). One hundred and forty-five young sedentary adults were
assigned to either (i) a control group (no exercise, n = 54), (ii) a moderate
intensity exercise group (MOD-EX, n = 48), or (iii) a vigorous intensity exercise
group (VIG-EX n = 43) by unrestricted randomization. No relevant adverse
events were recorded. 97 participants (34 men, 63 women) were included in
the final analysis (Control; n = 35, MOD-EX; n=31, and VIG-EX; n=31).We
observed no changes in BAT volume (Î Control: â22.2 ± 52.6ml; Î MOD-EX:
â15.5 ± 62.1ml, Î VIG-EX: â6.8 ± 66.4 ml; P = 0.771) or 18F-fluorodeoxyglucose
uptake (SUVpeak Î Control: â2.6 ± 3.1ml; Î MOD-EX: â1.2 ± 4.8, Î VIG-EX:
â2.2 ± 5.1; p = 0.476) in either the control or the exercise groups. Thus, we did
not find any evidence of an exercise-induced change on BAT volume or activity
in young sedentary adults.Spanish Government PI13/01393Retos de la Sociedad DEP2016-79512-R
PTA-12264IEuropean CommissionSpanish Government FPU13/04365
FPU14/04172
FPU15/04059
FPU16/03653
FPU19/01609Consejo Nacional de Ciencia y Tecnologia (CONACyT) 440575Fundacion Iberoamericana de Nutricion (FINUT)Redes Tematicas de Investigacion Cooperativa RETIC Red SAMID RD16/0022AstraZenecaUniversity of Granada Plan Propio de Investigacion 2016 -Excellence actions: Unit of Excellence on Exercise and Health (UCEES)Plan Propio de Investigacion 2018 -Programa Contratos-PuentePrograma Perfecionamiento de DoctoresJunta de Andalucia
Consejeria de Conocimiento, Investigacion y Universidades (ERDF) SOMM17/6107/UGRJunta de Andalucia P18-RT-4455Fundacion Alfonso Martin EscuderoMaria Zambrano fellowship by the Ministerio de Universidades y la Union Europea-NextGenerationEU RR_C_2021_04Novo Nordisk FoundationNovocure Limited NNF18OC003239
Scaling of intrinsic domain wall magnetoresistance with confinement in electromigrated nanocontacts
In this work we study the evolution of intrinsic domain wall magnetoresistance DWMR with domain wall confinement. Notched half ring nanocontacts are fabricated from Permalloy using a special ultrahigh vacuum electromigration procedure to tailor the size of the wire in situ and through the resulting domain wall confinement, we tailor the domain wall width from a few tens of nm down to a few nm. Through measurements of the dependence of the resistance with respect to the applied field direction, we extract the contribution of a single domain wall to the MR of the device, as a function of the width of the domain wall in the confining potential at the notch. In this size range, an intrinsic positive MR is found which dominates over anisotropic MR, as confirmed by comparison to micromagnetic simulations. Moreover, the MR is found to scale monotonically with the size of the domain wall, amp; 948;DW, as 1 amp; 948;bDW, with b 2.31 0.39. The experimental result is supported by quantum mechanical transport simulations based on ab initio density functional theory calculation
Direct Imaging of Chiral Domain Walls and Neel Type Skyrmionium in Ferrimagnetic Alloys
The evolution of chiral spin structures is studied in ferrimagnetic Ta Ir Fe GdFeCo Pt multilayers as a function of temperature using scanning electron microscopy with polarization analysis SEMPA . The GdFeCo ferrimagnet exhibits pure right handed N el type domain wall DW spin textures over a large temperature range. This indicates the presence of a negative Dzyaloshinskii Moriya interaction that can originate from both the top Fe Pt and the Co Pt interfaces. From measurements of the DW width, as well as complementary magnetic characterization, the exchange stiffness as a function of temperature is ascertained. The exchange stiffness is surprisingly more or less constant, which is explained by theoretical predictions. Beyond single skyrmions, it is identified by direct imaging a pure N el type skyrmionium, which due to the expected vanishing skyrmion Hall angle, is a promising topological spin structure to enable applications by next generation of spintronic device