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The bistability of ordered spin states in ferromagnets provides the basis for magnetic memory functionality. The latest generation of magnetic random access memories rely on an efficient approach in which magnetic fields are replaced by electrical means for writing and reading the information in ferromagnets. This concept may eventually reduce the sensitivity of ferromagnets to magnetic field perturbations to being a weakness for data retention and the ferromagnetic stray fields to an obstacle for high-density memory integration. Here we report a room-temperature bistable antiferromagnetic (AFM) memory that produces negligible stray fields and is insensitive to strong magnetic fields. We use a resistor made of a FeRh AFM, which orders ferromagnetically roughly 100 K above room temperature, and therefore allows us to set different collective directions for the Fe moments by applied magnetic field. On cooling to room temperature, AFM order sets in with the direction of the AFM moments predetermined by the field and moment direction in the high-temperature ferromagnetic state. For electrical reading, we use an AFM analogue of the anisotropic magnetoresistance. Our microscopic theory modelling confirms that this archetypical spintronic effect, discovered more than 150 years ago in ferromagnets, is also present in AFMs. Our work demonstrates the feasibility of fabricating room-temperature spintronic memories with AFMs, which in turn expands the base of available magnetic materials for devices with properties that cannot be achieved with ferromagnets. Magnetic memory devices are typically based on ferromagnetic materials. Now, a memory resistor based on the antiferromagnetic alloy FeRh is demonstrated at room temperature.

The electron occupancy of 3d-orbitals determines the properties of transition metal oxides. This can be achieved, for example, through thin-film heterostructure engineering of AB O 3 oxides, enabling emerging properties at interfaces. Interestingly, epitaxial strain may break the degeneracy of 3 d - e g and t 2 g orbitals, thus favoring a particular orbital filling with consequences for functional properties. Here we disclose the effects of symmetry breaking at free surfaces of AB O 3 perovskite epitaxial films and show that it can be combined with substrate-induced epitaxial strain to tailor at will the electron occupancy of in-plane and out-of-plane surface electronic orbitals. We use X-ray linear dichroism to monitor the relative contributions of surface, strain and atomic terminations to the occupancy of 3z 2 -r 2 and x 2 -y 2 orbitals in La 2/3 Sr 1/3 MnO 3 films. These findings open the possibility of an active tuning of surface electronic and magnetic properties as well as chemical properties (catalytic reactivity, wettability and so on). The electron occupancy of 3 d -orbitals critically determines the properties of transition metal oxides. In this report, surface symmetry breaking is combined with substrate-induced epitaxial strain to tune the occupancy of surface electronic orbitals in ABO 3 perovskite epitaxial films.

In recent years, striking discoveries have revealed that two-dimensional electron liquids (2DEL) confined at the interface between oxide band-insulators can be engineered to display a high mobility transport. The recognition that only few interfaces appear to suit hosting 2DEL is intriguing and challenges the understanding of these emerging properties not existing in bulk. Indeed, only the neutral TiO 2 surface of (001)SrTiO 3 has been shown to sustain 2DEL. We show that this restriction can be surpassed: (110) and (111) surfaces of SrTiO 3 interfaced with epitaxial LaAlO 3 layers, above a critical thickness, display 2DEL transport with mobilities similar to those of (001)SrTiO 3 . Moreover we show that epitaxial interfaces are not a prerequisite: conducting (110) interfaces with amorphous LaAlO 3 and other oxides can also be prepared. These findings open a new perspective both for materials research and for elucidating the ultimate microscopic mechanism of carrier doping.

Interfacial magnetoelectric coupling is a viable path to achieve electrical writing of magnetic information in spintronic devices. For the prototypical Fe/BaTiO 3 system, only tiny changes of the interfacial Fe magnetic moment upon reversal of the BaTiO 3 dielectric polarization have been predicted so far. Here, by using X-ray magnetic circular dichroism in combination with high-resolution electron microscopy and first principles calculations, we report on an undisclosed physical mechanism for interfacial magnetoelectric coupling in the Fe/BaTiO 3 system. At this interface, an ultrathin oxidized iron layer exists, whose magnetization can be electrically and reversibly switched on and off at room temperature by reversing the BaTiO 3 polarization. The suppression/recovery of interfacial ferromagnetism results from the asymmetric effect that ionic displacements in BaTiO 3 produces on the exchange coupling constants in the interfacial-oxidized Fe layer. The observed giant magnetoelectric response holds potential for optimizing interfacial magnetoelectric coupling in view of efficient, low-power spintronic devices. Interfacial magnetoelectric coupling could lead to a new generation of memory devices. Here, Bertacco and colleagues observe a large electric-field switchable magnetoelectric coupling effect in iron/barium titanate heterostructures, which is due to a thin oxidized iron layer.

Recent studies in devices comprising metal antiferromagnets have demonstrated the feasibility of a novel spintronic concept in which spin-dependent phenomena are governed by an antiferromagnet instead of a ferromagnet. Here we report experimental observation of the anisotropic magnetoresistance in an antiferromagnetic semiconductor Sr 2 IrO 4 . Based on ab initio calculations, we associate the origin of the phenomenon with large anisotropies in the relativistic electronic structure. The antiferromagnet film is exchange coupled to a ferromagnet, which allows us to reorient the antiferromagnet spin-axis in applied magnetic fields via the exchange spring effect. We demonstrate that the semiconducting nature of our AFM electrode allows us to perform anisotropic magnetoresistance measurements in the current-perpendicular-to-plane geometry without introducing a tunnel barrier into the stack. Temperature-dependent measurements of the resistance and anisotropic magnetoresistance highlight the large, entangled tunabilities of the ordinary charge and spin-dependent transport in a spintronic device utilizing the antiferromagnet semiconductor. The change in the electrical properties of a ferromagnetic under the influence of a magnetic field depends strongly on field orientation. Marti et al. now show that this so-called anisotropic magnetoresistance is also evident in antiferromagnetic semiconductors, making them useful in spintronics.

The ability to control a magnetic phase with an electric field is of great current interest for a variety of low power electronics in which the magnetic state is used either for information storage or logic operations. Over the past several years, there has been a considerable amount of research on pathways to control the direction of magnetization with an electric field. More recently, an alternative pathway involving the change of the magnetic state (ferromagnet to antiferromagnet) has been proposed. In this paper, we demonstrate electric field control of the Anomalous Hall Transport in a metamagnetic FeRh thin film, accompanying an antiferromagnet (AFM) to ferromagnet (FM) phase transition. This approach provides us with a pathway to “hide” or “reveal” a given ferromagnetic region at zero magnetic field. By converting the AFM phase into the FM phase, the stray field, and hence sensitivity to external fields, is decreased or eliminated. Using detailed structural analyses of FeRh films of varying crystalline quality and chemical order, we relate the direct nanoscale origins of this memory effect to site disorder as well as variations of the net magnetic anisotropy of FM nuclei. Our work opens pathways toward a new generation of antiferromagnetic – ferromagnetic interactions for spintronics.

Control of oral anticoagulant treatment has been reported to be suboptimal, but previous studies suggest that patient self-management improves control. To compare the quality of control and the clinical outcomes of oral anticoagulant treatment in self-managed patients versus patients following conventional management. Randomized, controlled trial. University-affiliated hospital in Spain. 737 patients with indications for anticoagulant treatment. The self-management group (n = 368) received simple instructions for using a portable coagulometer weekly and self-adjusting treatment dose. The conventional management group (n = 369) received usual care in an anticoagulation clinic (monthly measurement and control of international normalized ratio [INR], managed by hematologists). Percentage of INR values within the target range and major related complications. The median follow-up period was 11.8 months (range, 0.3 to 16.9 months). The unadjusted percentages of in-range INRs were 58.6% in the self-management group and 55.6% in the conventional management group (difference, 3.0 percentage points [95% CI, 0.4 to 5.4 percentage points]). Twenty-seven patients (7.3%) in the conventional management group and 8 (2.2%) in the self-management group had major complications related to anticoagulant treatment. The unadjusted risk difference for major complications between groups was 5.1 percentage points (exact 95% CI, 1.7 to 8.5 percentage points). Fewer patients had minor hemorrhages in the self-management group (14.9%) than in the conventional management group (36.4%). Fifteen patients (4.1%) in the conventional management group and 6 (1.6%) in the self-management group died (unadjusted risk difference, 2.5 percentage points [exact 95% CI, 0.0 to 5.1 percentage points]). The trial was performed at only 1 center and was not blinded. The dropout rate in the intervention group was 21%. Compared with conventional management by an anticoagulation clinic, self-management of oral anticoagulant treatment achieved a similar level of control. Of note, major complications and minor hemorrhages were less common in the self-management group.

A successful outcome of pregnancy requires an efficient uteroplacental vascular system. Since this system may be compromised by disorders of haemostasis associated with a prothrombotic state, we postulated that maternal thrombophilia might be a risk factor for fetal loss. We studied the relation between heritable thrombophilic defects and fetal loss in a cohort of women with factor V Leiden or deficiency of antithrombin, protein C, or protein S. We studied 1384 women enrolled in the European Prospective Cohort on Thrombophilia (EPCOT). Of 843 women with thrombophilia 571 had 1524 pregnancies; of 541 control women 395 had 1019 pregnancies. The controls were partners of male members of the EPCOT cohort or acquaintances of cases. We analysed the frequencies of miscarriage (fetal loss at or before 28 weeks of gestation) and stillbirth (fetal loss after 28 weeks of gestation) jointly and separately. The risk of fetal loss was increased in women with thrombophilia (168/571 vs 93/395; odds ratio 1 35 [95% CI.1 01–1·82]). The odds ratio was higher for stillbirth than for miscarriage (3·6 [14–9·4] vs 1·27 [0·94–1·71]). The highest odds ratio for stillbirth was in women with combined defects (14·3 [2·4–86·0]) compared with 5·2 (1·5–18·1) in antithrombin deficiency, 2·3 (0·6–8·3) in protein-C deficiency, 3·3 (1·0–11·3) in protein-S deficiency, and 2·0 (0·5–7·7) with factor V Leiden. The corresponding odds ratios for miscarriage in these subgroups were 0·8 (0·2–3·6), 17 (10–2·8), 14 (0·9–2·2), 12 (0·7–19), and 0·9 (0·5–15). Significantly more pregnancy terminations had been done in women with thrombophilia than in controls (odds ratio 2·9 [1·8–4·8]); this discrepancy was apparent in nine of 11 participating centres and for all thrombophilia subgroups. Women with familial thrombophilia, especially those with combined defects or antithrombin deficiency, have an increased risk of fetal loss, particularly stillbirth. Our findings have important implications for therapy and provide a rationale for clinical trials of thromboprophylaxis for affected women with recurrent fetal loss.

Epitaxial (001)-oriented NiFe2O4 films have been grown by RF magnetron sputtering on (001)MgAl2O4 substrates. In agreement with previous reports, magnetization loops of the thinner films reveal a saturation magnetization up to 3 times larger than the thicker films, which display values in agreement with the bulk. Here we discuss polarized neutron reflectivity experiments which are able to disregard that the magnetization overshoot is caused at the early stages of the growth.

The structure, magnetic response, and dielectric response of the grown epitaxial thin films of the orthorhombic phase of YMnO3 oxide on Nb:SrTiO3 (001) substrates have been measured. We have found that a substrate-induced strain produces an in-plane compression of the YMnO3 unit cell. The magnetization versus temperature curves display a significant zero-field cooling (ZFC)-field cooling hysteresis below the Néel temperature (TN ≈ 45 K). The dielectric constant increases gradually (up to 26%) below the TN and mimics the ZFC magnetization curve. We argue that these effects could be a manifestation of magnetoelectric coupling in YMnO3 thin films and that the magnetic structure of YMnO3 can be controlled by substrate selection and/or growth conditions.