Structure and magnetism of orthorhombic epitaxial FeMnAs

The molecular beam epitaxy growth of Fe on MnAs/GaAs(001) leads to the formation of an epitaxial FeMnAs phase at the Fe/MnAs interface. The investigation of the structure by high angle annular dark field imaging in a scanning transmission electron microscope reveals an unusual orthorhombic structure, with vacancy ordering. Ab initio calculations show an antiferromagnetic ground state for this orthorhombic FeMnAs.Fil: Demaille, Dominique. Laboratorio Internacional Franco-Argentino en Nanociencias; Francia. Universite Pierre et Marie Curie. Institut des Nanosciences de Paris; FranciaFil: Patriarche, Gilles. Centre National de la Recherche Scientifique; FranciaFil: Helman, Christian. Comisión Nacional de Energía Atómica; Argentina. Laboratorio Internacional Franco-Argentino en Nanociencias; FranciaFil: Eddrief, Mahmoud. Laboratorio Internacional Franco-Argentino en Nanociencias; Francia. Universite Pierre et Marie Curie. Institut des Nanosciences de Paris; FranciaFil: Etgens, Hugo. Laboratorio Internacional Franco-Argentino en Nanociencias; Francia. Universite Pierre et Marie Curie. Institut des Nanosciences de Paris; FranciaFil: Sacchi, Maurizio. Laboratorio Internacional Franco-Argentino en Nanociencias; Francia. Universite Pierre et Marie Curie. Institut des Nanosciences de Paris; Francia. L’Orme des merisiers Saint-Aubin. Synchrotron SOLEIL; FranciaFil: Llois, Ana Maria. Comisión Nacional de Energía Atómica; Argentina. Laboratorio Internacional Franco-Argentino en Nanociencias; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marangolo, Massimiliano. Laboratorio Internacional Franco-Argentino en Nanociencias; Francia. Universite Pierre et Marie Curie. Institut des Nanosciences de Paris; Franci

Prolonged pemetrexed infusion plus gemcitabine in refractory metastatic colorectal cancer: Preclinical rationale and phase II study results

Background. We investigated the cytotoxic activity of pemetrexed in combination with several drugs (gemcitabine, carboplatin, vinorelbine, and mitomycin C) using different exposure schedules in three colon cancer cell lines. The best results were obtained with the following schedule: a prolonged pemetrexed exposure followed by a 48-hour wash-out and then gemcitabine. This combination was then advanced to a phase II clinical trial. Methods. Patients with metastatic colorectal cancer in progression after standard treatment were included in the study. Adequate bonemarrow reserve, normal hepatic and renal function, and an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 were required. Treatment consisted of an 8-hour intravenous infusion of pemetrexed 150 mg/m 2 on day 1 and a 30-minute intravenous infusion of gemcitabine 1,000 mg/m 2 on day 3 of each cycle, repeated every 14 days. Results. Fourteen patients were enrolled onto the study (first step). No objective responses were seen, and evidence of stable disease was observed in only one of the 12 evaluable patients. The most important grade 3-4 side effects were hematological toxicity (neutropenia 64.2%, thrombocytopenia 71.4%, anemia 28.7%), fatigue (50.0%), and stomatitis (21.5%). Median overall survival and time to progression were 5.8 months (95% confidence interval [CI]: 3.9-7.1) and 2.1 months (95% CI: 1.7-2.8), respectively. Conclusion. The experimental pemetrexed-gemcitabine combination proved to be inactive and moderately toxic

Uniaxial anisotropy and temperature driven magnetization reversal of Fe deposited on a MnAs/GaAs(001) magnetic template

International audienceWe investigated the magnetic behavior of a 5 nm thick Fe layer deposited on a ferromagnetic MnAs/GaAs(001) template by using resonant magnetic scattering of polarized soft x rays. The Fe film displays in-plane uniaxial anisotropy and its magnetization can be modified and reversed by fine-tuning the substrate temperature around ambient because of the self-organization of the coexisting ferromagnetic and paramagnetic phases of the template

Thermally induced magnetization switching in Fe/MnAs/GaAs(001): selectable magnetic configurations by temperature and field control

International audienceSpintronic devices currently rely on magnetization control by external magnetic fields or spin-polarized currents. Developing temperature-driven magnetization control has potential for achieving enhanced device functionalities. Recently, there has been much interest in thermally induced magnetisation switching (TIMS), where the temperature control of intrinsic material properties drives a deterministic switching without applying external fields. TIMS, mainly investigated in rare-earth–transition-metal ferrimagnets, has also been observed in epitaxial Fe/MnAs/GaAs(001), where it stems from a completely different physical mechanism. In Fe/MnAs temperature actually modifies the surface dipolar fields associated with the MnAs magnetic microstructure. This in turn determines the effective magnetic field acting on the Fe overlayer. In this way one can reverse the Fe magnetization direction by performing thermal cycles at ambient temperatures. Here we use element selective magnetization measurements to demonstrate that various magnetic configurations of the Fe/MnAs/GaAs(001) system are stabilized predictably by acting on the thermal cycle parameters and on the presence of a bias field. We show in particular that the maximum temperature reached during the cycle affects the final magnetic configuration. Our findings show that applications are possible for fast magnetization switching, where local temperature changes are induced by laser excitations

Rotatable anisotropy of epitaxial Fe

We show by a combined magnetic force microscopy and synchrotron radiation spectroscopy study that stripe-like patterned magnetic domains are present in Fe1−xGax thin films. These stripes, whose origin is attributed to an out-of-plane magnetic component, can be rotated by an external magnetic field

Time resolved pump-probe scattering in MnAs/GaAs(001): A look into the dynamics of \u3b1-\u3b2 Stripe domains

Scattering of 130 nm radiation with 100 fs pulse length was used to monitor the \u3b1/\u3b2-striped microstructure in MnAs/GaAs(001), after a 390 nm 5 mJcm 122 pump pulse. A strong reduction of the Bragg peak intensity, corresponding to a widening of the \u3b2-stripes, takes place with a characteristic time of 15 ps. These results are relevant within the context of using MnAs/GaAs(001) as a template for the growth of ferromagnetic films, whose magnetization direction can be controlled by modifying the template temperature

Thermal switching of the magnetization in an iron film on a magnetically active template MnAs/GaAs(001)

International audienceWe show that the magnetization direction of a thin Fe film can be fully reversed in a thermal cycle of a few degrees close to room temperature, without making use of an external magnetic field. This result is obtained by depositing the Fe film on MnAs/GaAs(001), which displays a temperature-controlled self-organized pattern of submicron-wide stripes, alternating ferromagnetic and nonmagnetic phases. The temperature-dependent dipolar fields generated by this magnetically active template can be used to control the magnetization of the Fe overlayer