Monolithic AlGaAs second-harmonic nanoantennas: erratum

Figure 1(b) in [V. F. Gili et al, Opt. Express24, 15965 (2016)10.1364/OE.24.015965] is corrupted and is corrected in this erratum.

Serial cervical-length measurements after first episode of threatened preterm labor improve prediction of spontaneous delivery prior to 37 weeks' gestation

OBJECTIVE

To assess whether repeat cervical-length (CL) measurement in women discharged from hospital after their first episode of threatened preterm labor can predict their risk of spontaneous preterm birth.

METHODS

This was a secondary analysis of a randomized controlled trial of maintenance tocolysis, in which CL was measured on transvaginal ultrasound at the time of hospital discharge and after 2, 4, 8 and 12 weeks, in women who remained undelivered after their first episode of threatened preterm labor. After univariate analysis, multivariate logistic regression analysis was used to assess whether CL < 10 mm at the time of hospital discharge or at any follow-up evaluation could predict spontaneous delivery prior to 37 weeks of gestation.

RESULTS

Of 226 women discharged after a diagnosis of threatened preterm labor, 57 (25.2%) delivered spontaneously prior to 37 weeks' gestation. The risk of spontaneous preterm birth was higher among women with CL < 10 mm at hospital discharge compared to those with CL ≥ 10 mm (adjusted odds ratio (aOR), 3.3; 95% CI, 1.2-9.2). Moreover, spontaneous preterm delivery was more common when CL < 10 mm was detected up to 2 weeks (aOR, 2.9; 95% CI, 1.1-7.3) or up to 4 weeks (aOR, 7.3; 95% CI, 2.3-22.8) post discharge, as compared with when CL was persistently ≥ 10 mm. The association was not significant when considering CL measurements at 8 weeks, and there was insufficient information to assess the effect of measurements obtained at 12 weeks.

CONCLUSIONS

Women who remain undelivered after their first episode of threatened preterm labor continue to be at high risk of spontaneous preterm birth if their CL is below 10 mm at the time of hospital discharge or at any follow-up visit up to 4 weeks later. CL measurement could be included in the antenatal care of these women in order to stratify their risk of preterm birth, rationalize resource utilization and help clinicians improve pregnancy outcome. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Erratum: Fast Domain Wall Motion Governed by Topology and Œrsted Fields in Cylindrical Magnetic Nanowires [Phys. Rev. Lett. 123, 217201 (2019)]

This corrects the article DOI: 10.1103/PhysRevLett.123.217201.

Pnictogens Allotropy and Phase Transformation during van der Waals Growth

With their ns2 np3 valence electronic configuration, pnictogens are the only system to crystallize in layered van der Waals (vdW) and quasi-vdW structures throughout the group. Light pnictogens crystallize in the A17 phase, and bulk heavier elements prefer the A7 phase. Herein, we demonstrate that the A17 of heavy pnictogens can be stabilized in antimonene grown on weakly interacting surfaces and that it undergoes a spontaneous thickness-driven transformation to the stable A7 phase. At a critical thickness of ∼4 nm, A17 antimony transforms from AB- to AA-stacked α-antimonene by a diffusionless shuffle transition followed by a gradual relaxation to the A7 phase. Furthermore, the competition between A7- and A17-like bonding affects the electronic structure of the intermediate phase. These results highlight the critical role of the atomic structure and substrate-layer interactions in shaping the stability and properties of layered materials, thus enabling a new degree of freedom to engineer their performance.

Charge Redistribution Mechanisms in SnSe2 Surfaces Exposed to Oxidative and Humid Environments and Their Related Influence on Chemical Sensing

Tin diselenide (SnSe2) is a van der Waals semiconductor, which spontaneously forms a subnanometric SnO2 skin once exposed to air. Here, by means of surface-science spectroscopies and density functional theory, we have investigated the charge redistribution at the SnO2-SnSe2 heterojunction in both oxidative and humid environments. Explicitly, we find that the work function of the pristine SnSe2 surface increases by 0.23 and 0.40 eV upon exposure to O2 and air, respectively, with a charge transfer reaching 0.56 e-/SnO2 between the underlying SnSe2 and the SnO2 skin. Remarkably, both pristine SnSe2 and defective SnSe2 display chemical inertness toward water, in contrast to other metal chalcogenides. Conversely, the SnO2-SnSe2 interface formed upon surface oxidation is highly reactive toward water, with subsequent implications for SnSe2-based devices working in ambient humidity, including chemical sensors. Our findings also imply that recent reports on humidity sensing with SnSe2 should be reinterpreted, considering the pivotal role of the oxide skin in the interaction with water molecules.

ICD-detected respiratory disturbance index: accuracy for sleep apnea detection and prognostic value

Purpose

In patients affected by heart failure an association exists between sleep apnea (SA) measured by polysomnography and adverse outcome. Impedance-based implantable cardioverter defibrillator (ICD) algorithms have been designed to compute the Respiratory Disturbance Index (RDI) to identify severe SA. The purpose of the DASAP-HF study was to evaluate the accuracy of RDI for the prediction of severe SA, and investigate the prognostic value of device-detected RDI values.

Methods

Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed for 24 months. One month after implantation, patients underwent a polysomnographic study (PS) for assessing the apnea-hypopnea index (AHI). The average RDI value was calculated over a 1-week period preceding the sleep study and compared with the assessment of severe SA at PS (AHI ≥30 episodes/h). The endpoint was all-cause death after 24 months.

Results

224 out of 265 enrolled patients had usable RDI values. Patients characteristics: 79% male, 67±10 years, BMI 27±7kg/m2, ejection fraction 29±5%, 54% ischemic cardiomyopathy, 50% CRT-D. The mean AHI value at PS was 21±15 episodes/h. The mean RDI value recorded during the week preceding PS was 30±16 episodes/h. RDI values accurately identified severe SA diagnosed at PS (AUC 0.77; 95% CI 0.70–0.83; P=0.001). Based on the ROC curve analysis, RDI ≥29 episodes/h and AHI ≥17 episodes/h maximized sensitivity and specificity for the prediction of death. Both indexes were independently associated with all-cause death but, after correction for the other independent significant prognostic variables, RDI≥29episodes/h yielded stronger prediction (HR: 12.22, 95% CI:1.64–91.37, p=0.015) as compared to AHI ≥17episodes/h (HR: 4.14, 95% CI:1.17–14.66, p=0.028). Moreover, severe SA diagnosed at PS (AHI ≥30episodes/h) was not associated with death (HR: 1.20, 95% CI:0.3817–3.8266, p=0.761).

Conclusions

In heart failure patients indicated to ICD, severe SA was confirmed to be associated with survival. The ICD-measured RDI accurately identified severe SA detected at PS, and was associated with the risk of death at long-term.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Boston Scientific

Correction: Fine tuning of ferromagnet/antiferromagnet interface magnetic anisotropy for field-free switching of antiferromagnetic spins

Correction for 'Fine tuning of ferromagnet/antiferromagnet interface magnetic anisotropy for field-free switching of antiferromagnetic spins' by M. Slęzak et al., Nanoscale, 2020, DOI: 10.1039/d0nr04193a.

Fine tuning of ferromagnet/antiferromagnet interface magnetic anisotropy for field-free switching of antiferromagnetic spins

We show that in a uniform thickness NiO(111)/Fe(110) epitaxial bilayer system, at given temperature near 300 K, two magnetic states with orthogonal spin orientations can be stabilized in antiferromagnetic NiO. Field-free, reversible switching between these two antiferromagnetic states is demonstrated. The observed phenomena arise from the unique combination of precisely tuned interface magnetic anisotropy, thermal hysteresis of spin reorientation transition and interfacial ferromagnet/antiferromagnet exchange coupling. The possibility of field-free switching between two magnetic states in an antiferromagnet is fundamentally interesting and can lead to new ideas in heat assisted magnetic recording technology.

In-Plane Magnetic Domains and Néel-like Domain Walls in Thin Flakes of the Room Temperature CrTe2 Van der Waals Ferromagnet

The recent discovery of magnetic van der Waals (vdW) materials triggered a wealth of investigations in materials science and now offers genuinely new prospects for both fundamental and applied research. Although the catalog of vdW ferromagnets is rapidly expanding, most of them have a Curie temperature below 300 K, a notable disadvantage for potential applications. Combining element-selective X-ray magnetic imaging and magnetic force microscopy, we resolve at room temperature the magnetic domains and domain walls in micron-sized flakes of the CrTe₂ vdW ferromagnet. Flux-closure magnetic patterns suggesting an in-plane six-fold symmetry are observed. Upon annealing the material above its Curie point (315 K), the magnetic domains disappear. By cooling back the sample, a different magnetic domain distribution is obtained, indicating material stability and lack of magnetic memory upon thermal cycling. The domain walls presumably have Néel texture, are preferentially oriented along directions separated by 120°, and have a width of several tens of nanometers. Besides microscopic mapping of magnetic domains and domain walls, the coercivity of the material is found to be of a few millitesla only, showing that the CrTe₂ compound is magnetically soft. The coercivity is found to increase as the volume of the material decreases.

[The use of RCGO triggers in the obstetric - gynecological procedures: the impact on the reduction of adeverse events. The experience of the Lombardia Region]

The last few weeks of pregnancy are critical to a baby's health because important organs, including the brain and lungs, are not completely developed until the end of pregnancy. The adverse events during labor and childbirth can have very serious physical, psychological and financial consequences for the child, the family, health professionals and the whole community. These events can be reduced through interventions aimed at improving the safety and quality of care, based on evidence-based knowledge, guidelines and practices that must be widely and effectively applied. This work reports the experience of the Lombardy Region on improvement actions in the obstetric and gynecological procedures for the reduction of adverse events and sentinel events through the monitoring and management of the RCGS trigger tool.

Coherent x-ray scattering in an XPEEM setup

X-ray photoemission electron microscopy, one of the most successful imaging tools at synchrotrons, is known to have limitations related to the application of external fields and to the short electron mean free path. In order to overcome such issues, we adapt an existing XPEEM instrument to simultaneously perform coherent x-ray scattering measurements in reflectivity mode, thus adding a complementary method to XPEEM. Photon-in photon-out x-ray scattering provides the sensitivity to buried interfaces as well as the possibility to work under external fields, which is challenging when using charged particles for imaging. XPEEM, in turn, greatly alleviates the difficulties associated with the reconstruction methods used in coherent diffraction imaging. The combination of the two methods is demonstrated for an artifical spin-ice lattice showing both chemical and magnetic contrast.

Realization of Symmetry-Enforced Two-Dimensional Dirac Fermions in Nonsymmorphic α-Bismuthene

Two-dimensional (2D) Dirac-like electron gases have attracted tremendous research interest ever since the discovery of free-standing graphene. The linear energy dispersion and nontrivial Berry phase play a pivotal role in the electronic, optical, mechanical, and chemical properties of 2D Dirac materials. The known 2D Dirac materials are gapless only within certain approximations, for example, in the absence of spin-orbit coupling (SOC). Here, we report a route to establishing robust Dirac cones in 2D materials with nonsymmorphic crystal lattice. The nonsymmorphic symmetry enforces Dirac-like band dispersions around certain high-symmetry momenta in the presence of SOC. Through μ-ARPES measurements, we observe Dirac-like band dispersions in α-bismuthene. The nonsymmorphic lattice symmetry is confirmed by μ-low-energy electron diffraction and scanning tunneling microscopy. Our first-principles simulations and theoretical topological analysis demonstrate the correspondence between nonsymmorphic symmetry and Dirac states. This mechanism can be straightforwardly generalized to other nonsymmorphic materials. The results enlighten the search of symmetry-enforced Dirac fermions in the vast uncharted world of nonsymmorphic 2D materials.

Fast Domain Wall Motion Governed by Topology and Œrsted Fields in Cylindrical Magnetic Nanowires

While the usual approach to tailor the behavior of condensed matter and nanosized systems is the choice of material or finite-size or interfacial effects, topology alone may be the key. In the context of the motion of magnetic domain walls (DWs), known to suffer from dynamic instabilities with low mobilities, we report unprecedented velocities >600  m/s for DWs driven by spin-transfer torques in cylindrical nanowires made of a standard ferromagnetic material. The reason is the robust stabilization of a DW type with a specific topology by the Œrsted field associated with the current. This opens the route to the realization of predicted new physics, such as the strong coupling of DWs with spin waves above >600  m/s.

Spin structure and spin Hall magnetoresistance of epitaxial thin films of the insulating non-collinear antiferromagnet SmFeO3

We report a combined study of imaging the antiferromagnetic (AFM) spin structure and measuring the spin Hall magnetoresistance (SMR) in epitaxial thin films of the insulating non-collinear antiferromagnet SmFeO₃. X-ray magnetic linear dichroism photoemission electron microscopy measurements reveal that the AFM spins of the SmFeO₃(1 1 0) align in the plane of the film. Angularly dependent magnetoresistance measurements show that SmFeO₃/Ta bilayers exhibit a positive SMR, in contrast to the negative SMR expected in previously studied collinear AFMs. The SMR amplitude increases linearly with increasing external magnetic field at higher magnetic fields, suggesting that field-induced canting of the AFM spins plays an important role. In contrast, around the coercive field, no detectable SMR signal is observed, indicating that the SMR of the AFM and canting magnetization components cancel out. Below 50 K, the SMR amplitude increases sizably by a factor of two as compared to room temperature, which likely correlates with the long-range ordering of the Sm ions. Our results show that the SMR is a sensitive technique for non-equilibrium spin systems of non-collinear AFMs.

Evidence of Cascaded Third-Harmonic Generation in Noncentrosymmetric Gold Nanoantennas

The optimization of nonlinear optical processes on the nanoscale is a crucial step for the integration of complex functionalities into compact photonic devices and metasurfaces. In such systems, photon upconversion can be achieved with higher efficiencies via third-order processes, such as third-harmonic generation (THG), thanks to the resonantly enhanced volume currents. Conversely, second-order processes, such as second-harmonic generation (SHG), are often inhibited by the symmetry of metal lattices and of common nanoantenna geometries. SHG and THG processes in plasmonic nanostructures are generally treated independently because they typically represent small perturbations in the light-matter interaction mechanisms. In this work, we demonstrate that this paradigm does not hold for plasmon-enhanced nonlinear optics by providing evidence of a sum-frequency generation (SFG) process seeded by SHG, which sizably contributes to the overall THG yield. We address this mechanism by unveiling a characteristic fingerprint in the polarization state of the THG emission from gold noncentrosymmetric nanoantennas, which directly reflects the asymmetric distribution of second-harmonic fields within the structure and does not depend on the model one employs to describe photon upconversion. We suggest that such cascaded processes may also appear for structures that exhibit only moderate SHG yields. The presence of this peculiar mechanism in THG from plasmonic nanoantennas at telecommunication wavelengths allows us to gain further insight into the physics of plasmon-enhanced nonlinear optical processes. This could be crucial in the realization of nanoscale elements for photon conversion and manipulation operating at room temperature.

P2815Antiplatelet therapy with cangrelor in patients undergoing surgery after coronary stent implantation: a real-world bridging protocol experience

Background

Perioperative management of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) in patients deemed at high thrombotic risk undergoing non-deferrable surgery remains poorly defined. Cangrelor represents a potential treatment option as a “bridge” from discontinuation of oral P2Y12 receptor antagonists to surgical procedures, but data in this setting are still scant.

Purpose

We sought to describe a real-world experience of a bridging protocol using cangrelor for patients referred to relevant bleeding risk surgery requiring withdrawal of DAPT.

Methods

We collected data from 7 Italian centers on patients with previous PCI, still on DAPT, undergoing non-deferrable surgery which required discontinuation of one or both antiplatelet agents. A standardized bridging protocol using cangrelor infusion before and eventually after surgery was applied (Figure 1).

Results

Between December 2017 and January 2019, a total of 18 patients (mean age 70±10 years; male 85%) were enrolled. In the majority (89%) of patients, the index PCI was performed due to acute coronary syndrome (ACS) and 2±1.7 stents per patient were implanted. All patients required non-deferrable, intermediate-high bleeding risk surgery as pulmonary lobectomy, colectomy, endoscopic bladder surgery, paranasal sinus surgery, coronary artery by-pass surgery and valvular repair, hip replacement, endoscopy sphincterotomy. High thrombotic risk categories included PCI time <1 month, SCA time <3 months, stent failure occurrence, previous Absorb BVS implantation. Due to the surgical bleeding risk, discontinuation of P2Y12 inhibitor was required 5 days before surgery (ticagrelor, n=13; prasugrel=1; clopidogrel, n=5). All patients but 1 maintained aspirin through the perioperative phase. Cangrelor infusion was started at a bridging dose (0.75 mcg/kg/min) 3 days before planned surgery and was discontinued 6.9±1.5 hours before. After surgery, drainages were left in all patients but 3. In 56% of patients, cangrelor was resumed within 24 hours from surgery (mean time 9±7 hours) for a mean of 36±38 hours. Drainages were removed after discontinuation of cangrelor, in order to reduce bleeding complications. Within 2 hours from post-operative cangrelor discontinuation, a 300 mg clopidogrel loading dose was administered. No major ischemic adverse outcomes occurred during hospital stay and up to 30 days follow-up. The mean Hb drop was 2±1.8 g/dl, 7 patients received blood transfusions consistent with the type of surgeries and no life-threatening or fatal bleeding occurred.

Figure 1. Standardized bridging protocol.

Conclusions

Peri-operative bridge therapy with cangrelor is a feasible approach for stented patients at high thrombotic risk referred to non-deferrable surgery requiring DAPT discontinuation. Larger studies are warranted to support the safety of this strategy.

Pulse picking in synchrotron-based XPEEM

We report on a simple and cost-effective device for high-speed gating in photoemission electron microscopy (PEEM) with pulsed photon sources. This device is based on miniaturized electrode plates, which deflect the photoelectron beam inside the imaging column of the microscope so that it is either accepted or blocked in its path towards the detector. The gating device is optimized for installation on the Elmitec SPELEEM III microscope. Due to the compact design, it can be driven by voltage pulses of low amplitude (few volts), delivered by commercially available signal generators. Most notably, our device allows for stroboscopic data collection with on-time of less than 10 ns and at a rate in the range from 1 MHz to 250 MHz, making it suitable for usage in both hybrid and standard multi-bunch operation of the synchrotron ring. We demonstrate applications of pump-probe imaging at high lateral resolution, namely magnetic imaging and PEEM imaging of surface acoustic waves.

Layer-by-Layer Graphene Growth on β-SiC/Si(001)

The mechanism of few-layer graphene growth on the technologically relevant cubic-SiC/Si(001) substrate is uncovered using high-resolution core-level and angle-resolved photoelectron spectroscopy, low-energy electron microscopy, and microspot low-energy electron diffraction. The thickness of the graphitic overlayer supported on the silicon carbide substrate and related changes in the surface structure are precisely controlled by monitoring the progress of the surface graphitization in situ during high-temperature graphene synthesis, using a combination of microspectroscopic techniques. The experimental data reveal gradual changes in the preferential graphene lattice orientations at the initial stages of the few-layer graphene growth on SiC(001) and can act as reference data for controllable growth of single-, double-, and triple-layer graphene on silicon carbide substrates.

In-Gap States and Band-Like Transport in Memristive Devices

Point defects such as oxygen vacancies cause emergent phenomena such as resistive switching in transition-metal oxides, but their influence on the electron-transport properties is far from being understood. Here, we employ direct mapping of the electronic structure of a memristive device by spectromicroscopy. We find that oxygen vacancies result in in-gap states that we use as input for single-band transport simulations. Because the in-gap states are situated below the Fermi level, they do not contribute to the current directly but impact the shape of the conduction band. Accordingly, we can describe our devices with band-like transport and tunneling across the Schottky barrier at the interface.

Shaping the Nonlinear Emission Pattern of a Dielectric Nanoantenna by Integrated Holographic Gratings

We demonstrate the shaping of the second-harmonic (SH) radiation pattern from a single AlGaAs nanodisk antenna using coplanar holographic gratings. The SH radiation emitted from the antenna toward the-otherwise forbidden-normal direction can be effectively redirected by suitably shifting the phase of the grating pattern in the azimuthal direction. The use of such gratings allows increasing the SH power collection efficiency by 2 orders of magnitude with respect to an isolated antenna and demonstrates the possibility of intensity-tailoring for an arbitrary collection angle. Such reconstruction of the nonlinear emission from nanoscale antennas represents the first step toward the application of all-dielectric nanostructures for nonlinear holography.

Vaginal birth after prior myomectomy

OBJECTIVE

The aim of this retrospective cohort study was to evaluate the obstetrical and perinatal outcomes of vaginal birth in case of pregnancies achieved after prior myomectomy. We also analyzed how operative characteristics at the time of surgery might influence the choice of obstetricians about mode of delivery.

STUDY DESIGN

We analyzed retrospectively all women who underwent laparoscopic (LPS) or laparotomic (LPT) myomectomy between January 2002 and December 2014, in a network of three Institutions belonging to the University of Milano Bicocca, Italy. Women were contacted by phone interview and only cases with available follow-up data and who had a subsequent pregnancy were included. Operative characteristics and subsequent obstetrical outcomes were recorded and analyzed.

RESULTS

469 women who underwent myomectomy were contacted by phone interview, and 152 pregnancies were achieved after surgery, 96 after LPS and 56 after LPT. A total of 110 pregnancies ended in deliveries at ≥24 weeks. Seventy-three (66.4%) women had trial of labor after myomectomy (TOLAM), while 24 (21.8%) had a planned cesarean delivery (CD). Sixty-six (90.4%) of the TOLAM cases successfully accomplished vaginal delivery. No cases of uterine rupture (UR) were reported, and all deliveries ended in live births. The incidence of Neonatal Intensive Care Unit admission was 14.5% (16/110), with no cases of perinatal death. Comparing the surgical details at the time of myomectomy, the incidence of uterine cavity entered was significantly higher in planned CD group compared to TOLAM cases (p < 0.001). No other significant difference between the two groups was reported.

CONCLUSIONS

A successful vaginal delivery was accomplished by 90.4% of women who had TOLAM, without any case of UR or severe maternal and perinatal complications. TOLAM may be considered and offered as feasible and relatively safe option. Obstetricians' attitude toward mode of delivery after prior myomectomy seems to be influenced by the reported entry into the uterine cavity at the time of surgery.

Metal-dielectric hybrid nanoantennas for efficient frequency conversion at the anapole mode

Background: Dielectric nanoantennas have recently emerged as an alternative solution to plasmonics for nonlinear light manipulation at the nanoscale, thanks to the magnetic and electric resonances, the strong nonlinearities, and the low ohmic losses characterizing high refractive-index materials in the visible/near-infrared (NIR) region of the spectrum. In this frame, AlGaAs nanoantennas demonstrated to be extremely efficient sources of second harmonic radiation. In particular, the nonlinear polarization of an optical system pumped at the anapole mode can be potentially boosted, due to both the strong dip in the scattering spectrum and the near-field enhancement, which are characteristic of this mode. Plasmonic nanostructures, on the other hand, remain the most promising solution to achieve strong local field confinement, especially in the NIR, where metals such as gold display relatively low losses. Results: We present a nonlinear hybrid antenna based on an AlGaAs nanopillar surrounded by a gold ring, which merges in a single platform the strong field confinement typically produced by plasmonic antennas with the high nonlinearity and low loss characteristics of dielectric nanoantennas. This platform allows enhancing the coupling of light to the nanopillar at coincidence with the anapole mode, hence boosting both second- and third-harmonic generation conversion efficiencies. More than one order of magnitude enhancement factors are measured for both processes with respect to the isolated structure. Conclusion: The present results reveal the possibility to achieve tuneable metamixers and higher resolution in nonlinear sensing and spectroscopy, by means of improved both pump coupling and emission efficiency due to the excitation of the anapole mode enhanced by the plasmonic nanoantenna.

Magnetic Patterning by Electron Beam-Assisted Carbon Lithography

We report on the proof of principle of a scalable method for writing the magnetic state by electron-stimulated molecular dissociative adsorption on ultrathin Co on Re(0001). Intense microfocused low-energy electron beams are used to promote the formation of surface carbides and graphitic carbon through the fragmentation of carbon monoxide. Upon annealing at the CO desorption temperature, carbon persists in the irradiated areas, whereas the clean surface is recovered elsewhere, giving origin to chemical patterns with nanometer-sharp edges. The accumulation of carbon is found to induce an in-plane to out-of-plane spin reorientation transition in Co, manifested by the appearance of striped magnetic domains. Irradiation at doses in excess of 1000 L of CO followed by ultrahigh vacuum annealing at 380 °C determines the formation of a graphitic overlayer in the irradiated areas, under which Co exhibits out-of-plane magnetic anisotropy. Domains with opposite magnetization are separated here by chiral Neél walls. Our fabrication protocol adds lateral control to spin reorientation transitions, permitting to tune the magnetic anisotropy within arbitrary regions of mesoscopic size. We envisage applications in the nano-engineering of graphene-spaced stacks exhibiting the desired magnetic state and properties.