Adverse health effects from exposure to air pollution are a global challenge and of widespread concern. Recent high ambient concentration episodes of air pollutants in European cities highlighted the dynamic nature of human exposure and the gaps in data and knowledge about exposure patterns. In order to support health impact assessment it is essential to develop a better understanding of individual exposure pathways in people's everyday lives by taking account of all environments in which people spend time. Here we describe the development, validation and results of an exposure method applied in a study conducted in Scotland. A low-cost particle counter based on light-scattering technology - the Dylos 1700 was used. Its performance was validated in comparison with equivalent instruments (TEOM-FDMS) at two national monitoring network sites (R(2)=0.9 at a rural background site, R(2)=0.7 at an urban background site). This validation also provided two functions to convert measured PNCs into calculated particle mass concentrations for direct comparison of concentrations with equivalent monitoring instruments and air quality limit values. This study also used contextual and time-based activity data to define six microenvironments (MEs) to assess everyday exposure of individuals to short-term PM2.5 concentrations. The Dylos was combined with a GPS receiver to track movement and exposure of individuals across the MEs. Seventeen volunteers collected 35 profiles. Profiles may have a different overall duration and structure with respect to times spent in different MEs and activities undertaken. Results indicate that due to the substantial variability across and between MEs, it is essential to measure near-complete exposure pathways to allow for a comprehensive assessment of the exposure risk a person encounters on a daily basis. Taking into account the information gained through personal exposure measurements, this work demonstrates the added value of data generated by the application of low-cost monitors.

In recent years, the field of antiferromagnetic spintronics has been substantially advanced. Electric‐field control is a promising approach for achieving ultralow power spintronic devices via suppressing Joule heating. Here, cutting‐edge research, including electric‐field modulation of antiferromagnetic spintronic devices using strain, ionic liquids, dielectric materials, and electrochemical ionic migration, is comprehensively reviewed. Various emergent topics such as the Néel spin–orbit torque, chiral spintronics, topological antiferromagnetic spintronics, anisotropic magnetoresistance, memory devices, 2D magnetism, and magneto‐ionic modulation with respect to antiferromagnets are examined. In conclusion, the possibility of realizing high‐quality room‐temperature antiferromagnetic tunnel junctions, antiferromagnetic spin logic devices, and artificial antiferromagnetic neurons is highlighted. It is expected that this work provides an appropriate and forward‐looking perspective that will promote the rapid development of this field.

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Non-collinear antiferromagnetic materials have received dramatically increasing attention in the field of spintronics as their exotic topological features such as the Berry-curvature-induced anomalous Hall effect and possible magnetic Weyl states could be utilized in future topological antiferromagnetic spintronic devices. In this work, we report the successful integration of the antiferromagnetic metal Mn3Sn thin films onto ferroelectric oxide PMN-PT. By optimizing growth, we realized the large anomalous Hall effect with small switching magnetic fields of several tens mT fully comparable to those of bulk Mn3Sn single crystals, anisotropic magnetoresistance and negative parallel magnetoresistance in Mn3Sn thin films with antiferromagnetic order, which are similar to the signatures of the Weyl state in bulkMn3Sn single crystals. More importantly, we found that the anomalous Hall effect in antiferromagnetic Mn3Sn thin films can be manipulated by electric fields applied onto the ferroelectric materials, thus demonstrating the feasibility of Mn3Sn-based topological spintronic devices operated in an ultralow power manner. Experimental methodsMn3Sn films were grown on (001)-oriented MgO, 0.7PbMg1/3Nb2/3O3-0.3PbTiO3 (PMN-PT), 100-nm-thick LaAlO3-buffered PMN-PT substrates from a polycrstalline Mn3Sn target by a d.c. sputtering system with a base pressure of 7.5×10 -9 Torr. The growth temperature was 150 ˚C. The sputtering power and the Ar pressure during deposition were 60 W and 3 mTorr, respectively. The growth rate was ~0.28 Å/s as determined by transmission electron microscopy measurements. Co90Fe10 (CoFe) thin films were grown by the d.c. sputtering system as well. The sputtering power and the Ar pressure were 90 W and 3 mTorr, respectively. The growth rate was ~0.11 Å/s. Pt thin films were sputtered by 30 W at an Ar pressure of 3 mTorr. Its growth rate was 0.5 Å/s. The 100-nm-thick LaAlO3 buffer layers on PMN-PT substrates were fabricated by pulsed laser deposition with a laser fluence of ~1.6 J/cm 2 , an oxygen pressure of 10 -2 Torr and a repetition rate of 10 Hz at 800 ˚C. The focused laser spot size was 1×3 mm 2 and the target-substrate distance was 60 mm. The deposition rate of LaAlO3 is ~0.11 Å/pulse. A Quantum Design VersaLab system was used for conducting electrical and magnetic measurements. The measuring current was 1 mA supplied from a Keithley 2400 sourcemeter.A Keithley 2182A nanovolt meter was used to collect voltage signals for both longitudinal and transverse resistance measurements. The gate electric field was supplied by another Keithley 2400 sourcemeter. Results and discussionFirstly, by varying the growth temperature of Mn3Sn thin films onto (001)-oriented MgO single-crystal substrates from room temperature to 750 ˚C, we identified that the optimal growth temperature for achieving the most remarkable AHE and the lowest magnetic field for switching the anomalous Hall resistance is 150 ˚C. As shown in Fig. 1a, a 50-nm-thick Mn3Sn/MgO heterostructure fabricated at 150 ˚C exhibit a rather sharp inte...

One of the main bottleneck issues for room‐temperature antiferromagnetic spintronic devices is the small signal read‐out owing to the limited anisotropic magnetoresistance in antiferromagnets. However, this could be overcome by either utilizing the Berry‐curvature‐induced anomalous Hall resistance in noncollinear antiferromagnets or establishing tunnel‐junction devices based on effective manipulation of antiferromagnetic spins. In this work, the giant piezoelectric strain modulation of the spin structure and the anomalous Hall resistance in a noncollinear antiferromagnetic metal—D019 hexagonal Mn3Ga—is demonstrated. Furthermore, tunnel‐junction devices are built with a diameter of 200 nm to amplify the maximum tunneling resistance ratio to more than 10% at room‐temperature, which thus implies significant potential of noncollinear antiferromagnets for large signal‐output and high‐density antiferromagnetic spintronic device applications.

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The aim of this work was to compare the variability in an urban area of fine particles (PM2.5), ultrafine particles (UFP) and black carbon (BC) and to evaluate the relationship between each particle metric and potential factors (local traffic, street topography and synoptic meteorology) contributing to the variability. Concentrations of the three particle metrics were quantified using portable monitors through a combination of mobile and static measurements in the city of Edinburgh, UK. The spatial variability of UFP and BC was large, of similar magnitude and about 3 times higher than the spatial variability of PM0.5-2.5 (the PM size fraction actually quantified in this work). Highest inter-daily variability was observed for PM0.5-2.5, which was approximately 2 times higher than inter-daily variability of BC and UFP. Elevated concentrations of UFP and BC were observed along streets with high traffic volumes whereas PM0.5-2.5 showed less variation between streets and a footpath without road traffic. Both BC and UFP were significantly correlated with traffic counts, while no significant correlation between PM0.5-2.5 and traffic counts was observed. BC was significantly correlated with UFP, with significantly different regression slopes between working days and non-working days implying that the increased number of diesel powered heavy goods vehicles during working days contributed more to BC than to UFP. It is concluded that variations in BC and UFP concentrations were mainly determined by the nearby traffic count and varying background concentrations between days, while variation in PM0.5-2.5 concentration was mainly associated with regional sources. These findings imply the need for different policies for managing human exposure to these different particle components: control of much BC and UFP appears to be manageable at local scale by restricting traffic emissions; however, abatement of PM2.5 requires a more strategic approach, in cooperation with other regions and countries on emissions control to curb long-range transport of PM2.5 precursors