Abstract
Multi-orbital physics in quasi-two-dimensional electron gases (q2DEGs) triggers intriguing phenomena not observed in bulk materials, such as unconventional superconductivity and magnetism. ...Here, we investigate the mechanism of orbital selective switching of the spin-polarization in the oxide q2DEG formed at the (001) interface between the LaAlO
3
, EuTiO
3
and SrTiO
3
band insulators. By using density functional theory calculations, transport, magnetic and x-ray spectroscopy measurements, we find that the filling of titanium-bands with 3d
xz
/3d
yz
orbital character in the EuTiO
3
layer and at the interface with SrTiO
3
induces an antiferromagnetic to ferromagnetic switching of the exchange interaction between Eu-4f
7
magnetic moments. The results explain the observation of the carrier density-dependent ferromagnetic correlations and anomalous Hall effect in this q2DEG, and demonstrate how combined theoretical and experimental approaches can lead to a deeper understanding of emerging electronic phases and serve as a guide for the materials design of advanced electronic applications.
An auxetic behaviour is evidenced in CoFe2O4 thin films grown by pulsed laser deposition on (100) MgO substrates under various O2/N2 pressures. This rare behaviour for an intrinsic material is ...observed for intermediate oxidation conditions, in between two non auxetic domains delimited by high (>0.05 mbar) and low (<0.03 mbar) O2/N2 deposition pressures. Combining X-ray resonant diffraction and Mössbauer spectroscopy, we experimentally prove that the auxetic behaviour is related to the presence of cobalt ions in the tetrahedral sites. The impact of the structural modifications caused by the various oxidation conditions on the electronic and magnetic properties are studied for the various oxidation domains. Variations as important as a transition from a p-type semiconducting to an insulating behaviour, or from an in-plane to an out-of-plane magnetization are observed when spanning from the lowest (0.01 mbar) to the highest (1 mbar) studied oxidation pressures.
Schematic representation of both crystallographic and magnetic properties of CoFe2O4 thin films as a function of their deposition pressure. Display omitted
•Modulation of properties of CoFe2O4 films from auxetic to non-auxetic is evidenced.•Tuning of the magnetic and electrical properties of the films is evidenced and explained.•Cationic distribution has been determined for all films using resonant x-ray diffraction.•Experimental proof is given for the theoretical model proposed by Fereiro-Vilas.
Studies on oxide quasi-two dimensional electron gas (q2DEG) have been a playground for the discovery of novel and sometimes unexpected phenomena, like the reported magnetism at the surface and at the ...interface between LaAlO$_{3}$ and SrTiO$_{3}$ non-magnetic materials. However, magnetism in this system is weak and there are evidences of a not intrinsic origin. Here, by using in-situ high-resolution angle resolved photoemission we demonstrate that ferromagnetic EuTiO$_{3}$, the magnetic counterpart of SrTiO$_{3}$ in the bulk, hosts a q2DEG at its (001) surface. This is confirmed by density functional theory calculations with Hubbard U terms in the presence of oxygen divacancies in various configurations, all of them leading to a spin-polarized q2DEG related to the ferromagnetic order of Eu-4f magnetic moments. The results suggest EuTiO$_{3}$(001) as a new material platform for oxide q2DEGs, characterized by broken inversion and time reversal symmetries.
Background: The role of allergens in the severity of tomato allergy symptoms has not yet been studied. Objectives: To evaluate the relationship between severe allergic reactions to peach and tomato ...and between tomato allergy symptoms and the pattern of IgE positivity for rPru p 1, rPru p 3, rPru p 4, rBet v 1, rBet v 2, rBet v 4, rPhl p 1, and rPhl p 12 in order to identify the role of recombinant allergens in the severity of reactions to tomato. Methods: We studied peach-allergic patients with clinical reactions to tomato by performing an open food challenge, skin prick test, and determination of serum specific IgE to tomato and to recombinant peach, birch, and grass allergens. Statistical analysis was carried out to evaluate the relationship between the severity of tomato symptoms and IgE positivity to the different allergens and to peach-induced symptoms. Results: We found a significant association between severe reactions to tomato and severe reactions to peach (P=.017) and levels of IgE to rPru p 3 (P=.029) and between mild tomato allergy symptoms and levels of IgE to rPru p 1 (P=.047), anti-rBet v 1 (P=.0414), anti-rBet v 2 (P=.0457), and Phleum pratense (P=.0022). Conclusion: We observed a significant relationship between peach and symptoms of tomato allergy. IgE positivity for rPru p 3 seems to be a surrogate biochemical marker for severe tomato allergy, whereas the presence of anti-rPru p 1 IgE may be an indicator of mild tomato allergy.
Superconductivity in infinite-layer nickelates holds exciting analogies with that of cuprates, with similar structures and 3d-electron count. Using resonant inelastic x-ray scattering, we studied ...electronic and magnetic excitations and charge density correlations in Nd1-xSrxNiO2 thin films with and without an SrTiO3 capping layer. We observe dispersing magnons only in the capped samples, progressively dampened at higher doping. We detect an elastic resonant scattering peak in the uncapped x=0 compound at wave vector (∼⅓,0), remindful of the charge order signal in hole doped cuprates. The peak weakens at x=0.05 and disappears in the superconducting x=0.20 film. The role of the capping on the electronic reconstruction far from the interface remains to be understood.
Buckwheat allergy is considered a rare food allergy outside of Asia. In Europe, buckwheat has been described mainly as a hidden allergen. Data on the prevalence of buckwheat hypersensitivity in ...non-Asian countries is very poor. The aim of this multicenter study was to evaluate the prevalence of buckwheat sensitization and its association with other sensitizations among patients referred to allergy clinics in different geographic areas of Italy. All patients referred to 18 Italian allergy clinics from February through April 2011 were included in the study and evaluated for sensitization to buckwheat and other allergens depending on their clinical history. A total of 1,954 patients were included in the study and 61.3% of them were atopic. Mean prevalence of buckwheat sensitization was 3.6% with significant difference between Northern (4.5%), Central (2.2%) and Southern (2.8%) regions. This is, to our knowledge, the largest epidemiological survey on buckwheat allergy reported outside of Asia. Buckwheat is an emerging allergen in Italy, being more frequently associated to sensitization in Northern regions.
We attempt to grow perovskite CaTiS3 by pulsed laser deposition (PLD) on various substrates using a CaS:TiS2 target. Using Al2O3 (0001) substrates at 600 °C deposition temperature in vacuum, ...Ca1.0Ti1.05S2.48Oy stoichiometry is measured by Energy-dispersive X-ray spectroscopy (EDS) and Ca1.0Ti1.0S2.0O0.7 by Rutherford Backscattering Spectrometry (RBS). This indicates that when the films are grown in vacuum at moderate temperature, a high amount of S can be transferred from the target to the film. While no phase segregation of CaS and TiS2 could be observed, no perovskite CaTiS3 phase could be obtained, but rather a phase governed by van der Waals interactions. The films show a highly doped n-type semiconductor behavior with absorption coefficient in the 105 cm−1 range at 350–2500 nm but no surface photovoltage signal. This work should stimulate further experimental efforts in PLD growth of chalcogenides and chalcogenide perovskites.
•Films are grown by pulsed laser deposition (PLD) from a CaS:TiS2 target on various substrates.•The desired CaTiS3 perovskite phase could not be obtained but rather a van der Waals-related structure.•A large amount of S can be transferred from the target to the substrate at 600–700 °C in vacuum.•The films form a highly-doped n-type semiconductor with absorption coefficient in the 105 cm−1 range in the visible.
Approximately 2 million women in the USA and Europe continue taking oral contraceptives each year during undetected pregnancy due primarily to non-compliance and also to individual variation in ...sensitivity to hormones in the contraceptives. Prenatal exposure to oral contraceptives containing 17α-ethinyl oestradiol (EE) has generally not been associated with an increased incidence of externally observable malformations at birth. The purpose of this study was to assess effects on reproductive organs in adult male mice that had been exposed during gestation day 0 through 17 (equivalent to gestation week 16 in humans) to clinically relevant (~0.5 μg/kg/day) and lower doses of EE. Doses used in this study ranged from 0.002 to 2 μg/kg/day. By 5 months of age, prostate weight was significantly (P < 0.05) higher than controls in most treatment groups of EE (0.02–2 μg/kg). Prostatic androgen receptor populations were significantly elevated only in the 0.02 μg/kg group, suggesting different mechanisms for the increase in prostate weight at different doses. Daily sperm production (DSP) and DSP per gramme of testis were reduced in all treatment groups during adolescence, but not later in adulthood. These findings are consistent with prior studies showing that prenatal exposure of mice to very low doses of a number of oestrogenic chemicals can alter the adult male reproductive system without causing gross external malformations.
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