Spin-Hall magnetoresistance and spin Seebeck effect in spin-spiral and paramagnetic phases of multiferroic CoCr2O4 films

We report on the spin-Hall magnetoresistance (SMR) and spin Seebeck effect (SSE) in multiferroic CoCr2O4 (CCO) spinel thin films with Pt contacts. We observe a large enhancement of both signals below the spin-spiral (Ts = 28 K) and the spin lock-in transitions (T_{lock_in} = 14 K). The SMR and SSE response in the spin lock-in phase are one order of magnitude larger than those observed at the ferrimagnetic transition temperature (Tc = 94 K), which indicates that the interaction between spins at the Pt|CCO interface is more efficient in the non-collinear magnetic state below Ts and T_{lock-in}. At T > Tc, magnetic field-induced SMR and SSE signals are observed, which can be explained by a high interface susceptibility. Our results show that the spin transport at the Pt|CCO interface is sensitive to the magnetic phases but cannot be explained solely by the bulk magnetization

Super switching and control of in-plane ferroelectric nanodomains in strained thin films

With shrinking device sizes, controlling domain formation in nanoferroelectrics becomescrucial. Periodic nanodomains that self-organize into so-called ‘superdomains’ have beenrecently observed, mainly at crystal edges or in laterally confined nanoobjects. Here we showthat in extended, strain-engineered thin films, superdomains with purely in-plane polarizationform to mimic the single-domain ground state, a new insight that allows a priori design ofthese hierarchical domain architectures. Importantly, superdomains behave like strain-neutralentities whose resultant polarization can be reversibly switched by 90 deg, offering promisingperspectives for novel device geometries

Excess manganese as the origin of the low-temperature anomaly in NiMnSb

<p>The archetype of half-metallic magnetism, NiMnSb, has been reported to show an anomaly at low temperature. The high degree of spin polarization of the conduction electrons, characteristic of a half metal, is lost above this temperature. Recently reported experiments show that this anomaly is not an intrinsic property of NiMnSb: it requires an excess of (interstitial) manganese. Electronic structure calculations reported here show that the excess manganese orders antiferromagnetically with respect to the host magnetization, reduces the half-metallic band gap, and pushes the top of the valence band up to 36 meV below the Fermi level. Thermal excitations from minority to majority spin channel induce an avalanche effect, leading to the disordering of the magnetic moments of the excess manganese. This mechanism is supported by measurements of the magnetization as a function of temperature on NiMn1.05Sb: It shows a maximum in the magnetization measured in a field of 400 Oe.</p>

Chemical Solution Deposition of Ordered 2D Arrays of Room-Temperature Ferrimagnetic Cobalt Ferrite Nanodots

Over the past decades, the development of nano-scale electronic devices and high-density memory storage media has raised the demand for low-cost fabrication methods of two-dimensional (2D) arrays of magnetic nanostructures. Here, we present a chemical solution deposition methodology to produce 2D arrays of cobalt ferrite (CFO) nanodots on Si substrates. Using thin films of four different self-assembled block copolymers as templates, ordered arrays of nanodots with four different characteristic dimensions were fabricated. The dot sizes and their long-range arrangement were studied with scanning electron microscopy (SEM) and grazing incident small-angle X-ray scattering (GISAXS). The structural evolution during UV/ozone treatment and the following thermal annealing was investigated through monitoring the atomic arrangement with X-ray absorption fine structure spectroscopy (EXAFS) and checking the morphology at each preparation step. The preparation method presented here obtains array types that exhibit thicknesses less than 10 nm and blocking temperatures above room temperature (e.g., 312 K for 20 nm diameter dots). Control over the average dot size allows observing an increase of the blocking temperature with increasing dot diameter. The nanodots present promising properties for room temperature data storage, especially if a better control over their size distribution will be achieved in the future

Glyco-iELISA: a highly sensitive and unambiguous serological method to diagnose STEC-HUS caused by serotype O157

Background: Providing proof of presence of Shiga toxin–producing E. coli (STEC) infection forms the basis for differentiating STEC-hemolytic uremic syndrome (HUS) and atypical HUS. As the gold standard to diagnose STEC-HUS has limitations, using ELISA to detect serum antibodies against STEC lipopolysaccharides (LPS) has proven additional value. Yet, conventional LPS-ELISA has drawbacks, most importantly presence of cross-reactivity due to the conserved lipid A part of LPS. The newly described glyco-iELISA tackles this issue by using modified LPS that eliminates the lipid A part. Here, the incremental value of glyco-iELISA compared to LPS-ELISA is assessed. Methods: A retrospective study was performed including all pediatric patients (n = 51) presenting with a clinical pattern of STEC-HUS between 1990 and 2014 in our hospital. Subsequently, the diagnostic value of glyco-iELISA was evaluated in a retrospective nationwide study (n = 264) of patients with thrombotic microangiopathy (TMA). LPS- and glyco-iELISA were performed to detect IgM against STEC serotype O157. Both serological tests were compared with each other and with fecal diagnostics. Results: Glyco-iELISA is highly sensitive and has no cross-reactivity. In the single-center cohort, fecal diagnostics, LPS-ELISA, and glyco-iELISA identified STEC O157 infection in 43%, 65%, and 78% of patients, respectively. Combining glyco-iELISA with fecal diagnostics, STEC infection due to O157 was detected in 89% of patients. In the nationwide cohort, 19 additional patients (8%) were diagnosed with STEC-HUS by glyco-iELISA. Conclusion: This study shows that using glyco-iELISA to detect IgM against STEC serotype O157 has clear benefit compared to conventional LPS-ELISA, contributing to optimal diagnostics in STEC-HUS.Fil: Wijnsma, Kioa. Radboud Universiteit Nijmegen; Países BajosFil: Veissi, Susan T.. Radboud Universiteit Nijmegen; Países BajosFil: van Bommel, Sheila A. M.. Radboud Universiteit Nijmegen; Países BajosFil: Heuver, Rik. Radboud Universiteit Nijmegen; Países BajosFil: Volokhina, Elena B.. Radboud Universiteit Nijmegen; Países BajosFil: Comerci, Diego José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Ugalde, Juan Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín; ArgentinaFil: van de Kar, Nicole C. A. J.. Radboud Universiteit Nijmegen; Países BajosFil: van den Heuvel, Lambertus P. W. J.. Radboud Universiteit Nijmegen; Países Bajo