Poster Session

1 - Chirality switching and propagation control of a vortex domain wall in ferromagnetic nanotubes.

J. A. Otálora, J. A. López-López, P. Vargas, and P. Landeros

Universidad Técnica Federico Santa María, Valparaíso, Chile

We propose a procedure to manipulate the chirality and propagation of a vortex domain wall in ferromagnetic nanotubes by applying magnetic field pulses. It is found that the chiral state of the vortex wall can be switched, provided that (1) the field amplitude is between two critical values, the so-called chiral field and the well-known Walker field, and (2) the pulse length is longer than a critical time, which is the time needed by the wall to overcome a local energy barrier. These key parameters are estimated for Permalloy nanotubes and range between a few miliTesla and some nanoseconds.

2 - Domain wall manipulation in magnetic nanotubes induced by electric current pulses.

J. A. Otálora, J. A. López-López, A. S. Núñez, and P. Landeros

Universidad Técnica Federico Santa María, Valparaíso, Chile

We propose that the injection of electric currents can be used to manipulate independently the position and chirality of vortex-like domain walls in metallic ferromagnetic nanotubes. We support this proposal upon theoretical and numerical assessment of the magnetization dynamics driven by such currents. We show that proper interplay between the tube geometry, magnitude of the electric current and the duration of a current pulse, can be used to manipulate the position, velocity and chirality of a vortex domain wall. Our calculations suggest that domain wall velocities greater than 1 km -1 can be achieved for tube diameters of the order of 30 nm and increasing with it. We also find that the transition from steady to precessional domain wall motion occurs for very high electric current densities, of the order of 1013 A m-2. Furthermore, the great stability displayed by such chiral magnetic configurations, and the reduced Ohmic loses provided by the current pulses, lead to highly reproducible and efficient domain wall reversal mechanisms.

3 - FINITE tunnel magnetoresistance in junctions with a zero magnetisation ferromagnetic electrode.

M. Bersweiler, M. Da Silva, K. Dumesnil, C. Dufour, M. Hehn, D. Pierre, D. Lacour, F. Montaigne, G. Lengaigne, S. Robert

Institut Jean Lamour (UMR CNRS 7198), Université de Lorraine, BP 239, F-54506 Vandoeuvre lès Nancy, France

Since the discovery of spin dependent tunneling across a Ge barrier by Jullière most efforts have been expensed to discover new tunnel barrier materials. The electrodes were made mainly using conventional magnetic 3d transition metals. The next challenges consist in using new materials to design electrodes with specific properties. A perfectly stable spin-polarized electrode could be for instance engineered with a half-metallic antiferromagnet or ferrimagnet, exhibiting ideally both 100% spin-polarization and very small or zero magnetization. Conventional ferrimagnetic Rare Earth/Transition Metal alloys have been already shown to exhibit interesting properties as electrode in magnetic tunnel junctions [1]. These ferrimagnets can give rise to spin-polarized current in their magnetic compensated state, where the zero magnetization state results from opposite spin orders. Read more ...

4 - Thin films of Fe(Phen)2(NCS)2 investigated by X-Ray absorption spectroscopy: New hints on the influence of the substrate.

Vincent Davesne1,2, Manuel Gruber1,2, Martin Bowen1, Samy Boukari1, Toshio Miyamashi2, Fabrice Sheurer1, Maximiliano Martins2, Victor Da Costa1, Loïc Joly1, Philippe Ohresser3, Wulf Wulfhekel2, Eric Beaurepaire1.

1 Institut de Physique et de Chimie des Matériaux de Strasbourg, France
2 Karlsruhe Institue of Technology, Germany
3 Synchrotron SOLEIL, France

Spin-crossover (SCO) molecules, such as Fe(Phen)2(NCS)2, have been under the spotlights for their exceptional intrinsic property: their ability to change their spin from/to a high spin (HS) state to/from a low spin (LS) state when submitted to an external stimuli, such as light, ligand exchange, heat, magnetic field. Recently, we have proven that it was possible to switch selectively and reversibly single Fe(Phen) molecules deposited on a CuN/Cu(100) surface[1]. Our aim has been consequently to investigate the properties of thicker films (a few monolayers). X-Ray absorption spectroscopty (XAS) studies on Cu(100) and Co/Cu(100) reveal that the thin films exhibit a coexistence of spin states. Also, while the first few monolayers are unswitchable in the temperature range used, the successive layers exhibit a gradual increase of "switchability", with a loss of cooperativity in the thermal transition compared to bulk samples. Read more ...

5 - Influence of the spin polarized electric current in the ferromagnetic resonance response of thin films.

R. A. Gallardo and P. Landeros

Departamento de Física, Universidad Técnica Federico Santa María, Valparaiso, Avenida España 1680, Valparaíso, Chile.

Based in the Slonczewski model for the spin-transfer in a spin valve system, we describe the influence of a spin polarized electric current on the ferromagnetic resonance response of a thin film. Here, the electric current is applied perpendicular to a trilayer structure composed by a polarizer ferromagnet, a non-magnetic metal and a free ferromagnet, and the equilibrium orientations of the polarizer and free layer magnetizations are arbitrary. A explicit formula for the response function (magnetic susceptibility) is derived, which enable us to obtain the relevant quantities of the system like the FMR frequency, linewidth and the critical currents. The expression of the critical current presented in this work has applicability for any system with any equilibrium configuration. The results derived are in concordance with previous theoretical results and goes beyond because allow us unify configurations like in-plane or out of-plane.

6 - Spectroscopic investigation of pinned moments in FeMn/Co exchange bias system with XMCD and XRMR.

Patrick Audehm1,Sebastian Brück2,3, Sebastian Macke4, Mathias Schmidt1, Gisela Schütz1, and Eberhard J. Goering1

1Max-Planck-Institute for Intelligent Systems (former Metals Research), Heisenbergstrasse 3, 70569 Stuttgart, Germany
2University of New South Wales, School of Physics, Sydney NSW 2052, Australia
3Australian Nuclear Science and Technology Organization, New Illawarra Rd., Menai NSW 2232, Australia
4Department of Physics and Astronomy, Univ. of British Columbia, 6224 Agricultural Road, Vancouver, Canada

Modern magnetic thin film devices are based on exchange bias (EB), i.e. an additional unidirectional anisotropy resulting in a shifted hysteresis of a ferromagnet (FM) in contact with an antiferromagnet (AF). The physical nature and microscopic origin of the EB is still unknown. Here we present a thorough spectroscopic investigation of rotatable and also on pinned uncompensated magnetic moments based on both, X-ray magnetic circular dichroism (XMCD) and X-ray Resonant Magnetic Reflectivity (XRMR), performed on polycrystalline Co/FeMn samples. Thick and thin ferromagnetic Co layers have been investigated, each optimized for XRMR and XMCD investigations of the underlying FeMn layer.

7 - Magnetism of self-organized CoPd nanodots by XMCD.

F. Scheurer1, H. Bulou1, C. Goyhenex1, L. Joly1, V. Speisser1, M. Romeo1, G. Schull1, F. Wilhelm2, A. Rogalev2, E. Otero3, and P. Ohresser3

1IPCMS, UMR7504 CNRS- Université de Strasbourg, 23 rue du Loess F-67034 Strasbourg Cedex (France)
2ESRF BP220 Grenoble Cedex (France)
3Synchrotron-SOLEIL, L'Orme des merisiers Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex (France)

Self-organization allows to obtain collections of ordered arrays of clusters which can be used to measure individual physical properties as a function of cluster size and size distribution. Nanostructurated surfaces, such as reconstructed surfaces and vicinal ones, provide a way to analyze chemical and magnetic properties of collections of 3d or 4d metals [1-4], but also to understand fundamental mechanisms of adatom diffusion on an inhomogeneous surface [5]. The size of the clusters can easily be adjusted by varying the amount of deposited material. Growing alloy clusters allows adding a new control parameter, namely the concentration of the different species, which may modify the chemical and physical properties of the system. Highly ordered arrays of of CoxPd1-x bimetallic clusters on Au(111) were obtained in a wide concentration range by codeposition of Co and Pd. The relationship between the cluster shape and the concentration is analyzed and, resorting to atomistic simulations, the formation and relaxation mechanisms of these alloy clusters are determined. Magnetic properties as a function of Co concentration are analyzed by x-ray magnetic circular dichroism. Read more ...

8 - Robust Exchange Coupling in a CoO/FePt Film Grown on a Pt(001) Single Crystal.

Anne D. Lamirand, Márcio M. Soares, Hélio C. N. Tolentino, Maurizio De Santis, Aline Y. Ramos, Júlio C. Cezar, Abner De Siervo, Matthieu Jamet.

9 - Ultrafast Magnetization Dynamics of Lanthanide based materials.

N. Bergeard1, J. Wieczorek1, A. Eschenlohr2, A. Melnikov3, C. Stamm2, T. Kachel2, N. Pontius2, U. Bovensiepen1

1Universitat Duisburg-Essen, Fakultat fur Physik, Lotharstrasse 1, 47048 Duisburg, Germany
2Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH, BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
3Fritz-Haber-Institut der MPG, Phys. Chemie, Faradayweg 4-6, 14195 Berlin, Germany

Previous experiments performed on the fs-slicing end station at BESSY using tr-XMCD revealed that the demagnetization in Gd and Tb occurs on two subsequent timescales, associated with non-equilibrium (τ1) and quasi-equilibrium (τ2) regimes [1]. In the quasi-equilibrium process, the time scale (τ2) is set by direct spin-lattice coupling of 4f electron, explaining the faster (τ2,Tb=8ps) dynamics of Tb compare to Gd (τ2,Gd,Gd=40ps).
In a GdTb alloy the 4f magnetic moments of Gd are coupled to 4f moments of Tb by indirect exchange interaction [2]. Using tr-XMCD at the M5 edges of Gd and Tb, we observed an identical demagnetization time of 4f magnetic moments for both Gd and Tb in the GdTb alloy. Read more ...

10 - Synthesis and studies of novel 5-substituted Tris-(9-oxidophenalenone) aluminium complexes.

Andrea Magri1, Bernhard Schaefer1, Velimir Meded1,2, Mario Ruben1,3

1 Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany).
2 Steinbuch Centre for Computing, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany).
3Université de Strasbourg, Institute de Physique et Chimie des Matériaux de Strasbourg (France).

Design and synthesis of novel (in)organic materials with better electron transporting capability is an important pre-request for the realisation of efficient organic light emitting device[1]. In this regard we envisioned to synthesize novel organic ligands based on 9-Hydroxyphenalenone by introducing appropriate substituents at the position 5. Variety of substituents with electron donating, withdrawing and conformation directing capacities were introduced by adopting a Suzuki coupling procedure followed by a ring closing reaction [2]. The aforementioned ligands were complexed with aluminium salts. To check the possibility of incorporating the novel molecular frameworks in optoelectronic devices, electronic, photophysical properties and sublimation of the aluminium complexes were investigated. Read more ...

11 - Nature of the magnetic coupling in Co/MnF2 bilayers: Combined studies by using VT v-KERR and XMCD.

J. L. F. Cuñado, C. Rodrigo, P. Perna, A. Bollero, F.Terán, N. S. Sokolov, S. Gastev, S. Suturi, A. Banshikof, V. Fedorov, D.Baranov, K. Koshmak, L. Pasquali, J. Nogués, J. Camarero, R. Miranda.

We present a detailed study of temperature dependence of magnetization reversal properties in artificial magnetic nanostructures, by using a new experimental set-up that allows us to measure simultaneously magneto-resistance and vectorial-Kerr hysteresis loops at full angular range of the applied field angle, and in a broad temperature range (4 K to 500 K). Co/MnF2 bilayers have been studied using this device. New exchange bias phenomena at room temperature have been found, in particular, field-induced exchange bias above the MnF2 Néel temperature. Comparison with element-sensitive XCMD measurements is made to confirm the observed exchange bias behavior.

12 - Investigation of Magneto-Optical Properties of Co-based Multilayers.

Yanyan Yuan1, Karine Le Guen1, Jean-Michel André1, Zhanshan Wang2, Haochuan Li2, Jingtao Zhu2, Christian Mény3, Philippe Jonnard1

1 Laboratoire de Chimie Physique - Matière et rayonnement, Université Pierre et Marie Curie, CNRS, UMR 7614, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05, France.
2 Institute of Precision Optical Engineering Department of Physics, Tongji University, Shanghai 200092, China.
3 Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS-Université de Strasbourg, 23 rue du Loess, 67034 Strasbourg, France.

The Co-based multilayers have been shown promising optical mirrors for application in the EUV and soft x-ray ranges. The Mg/Co-based and Co/Mo2C multilayers are prepared by the magnetron sputtering in a high vacuum. The resonant magnetic reflectivity of Mg/Co-based multilayers around the Co L3 absorption edge is measured on a specifically designed sample with a circularly polarized incident radiation. The results show that the reflectivity of Mg/Co/B4C and Mg/Co multilayers are better than that of Mg/B4C/Co multilayer. The dichroic signal, which is the difference between the two reflectivities measured with the magnetic field applied in two opposite directions parallel to the sample surface, is obtained. The dichroic signal is more sensitive to Mg/Co multilayer than two others for the 1st, 2nd and 4th Bragg peaks. Then the magnetic properties of Co/Mo2C multilayer, which is designed to work in the soft x ray range and is annealed up to 600°C, are characterized by the magneto-optical Kerr effect (MOKE) and nuclear magnetic resonant (NMR) spectroscopy. An intense line at 221MHz is clearly observed on the samples annealed at temperatures higher than or equal to 300°C. The results reveal that Co/Mo2C multilayers possess good thermal stability and that the interfaces are subject to ordering or demixing upon annealing.

13 - Resonant Soft X-ray Scattering on Artificial Spin Ice.

J. Perron1,2, L. Anghinolfi1, N. Jaouen3, J.M. Tonnerre4, J. Lüning2, F. Nolting1, L.J. Heyderman1

1 Paul Scherrer Institut, Villigen PSI, Switzerland
2 Laboratoire de Chimie-Physique - Matière et Rayonnement (UMR 7614 UPMC/CNRS), Université Pierre et Marie Curie, Paris, France
3 Synchrotron SOLEIL, Gif-sur-Yvette, France
4 Institut Néel (UPR 2940 CNRS/UJF), Université Joseph Fourier, Grenoble, France

Artificial spin ice consists of dipolar coupled nanomagnets arranged on the sites of a kagome or square lattice, and is frustrated because all dipolar interactions at a vertex where the nanomagnets meet cannot be minimized simultaneously [1,2]. These systems are usually studied using microscopy techniques such as magnetic force microscopy, Lorentz microscopy and photoemission electron microscopy [3]. Another possibility is to use scattering techniques, which give information on magnetic correlations for large arrays of nanomagnets at length and timescales not accessible by microscopy techniques. In the present work, we employ a CCD camera to measure x-ray scattering patterns directly in two dimensions, thus providing a complete picture of the reciprocal space and the position of the Bragg peaks. Read more ...


P. Mazalski1, Z. Kuranti1, A. Maziewski1, M.O. Liedke2, J. Fassbender2, L.T. Baczewski3, A. Wawro3, A. Rogalev4, and F. Wilhelm4

1 Laboratory of Magnetism, Faculty of Physics, University of Białystok, Lipowa 41, 15-424 Białystok, Poland
2 Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden, Germany
3 Institute of Physics, Polish Academy of Science, Aleja Lotników 32, 02-668 Warszawa, Poland
4 European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble Cedex, France

Magnetic properties of ultrathin films are usually tuned by varying the film thickness, chemical composition or structure (see e.g. [1,2]). It has been demonstrated that magnetic properties of thin films with perpendicular magnetic anisotropy of interfacial origin may be also tuned by ions irradiation [3]. A Pt/Co/Pt trilayer irradiated by different ions exhibits the out-of-plane to in-plane magnetization reorientation phase transition. Moreover, it was shown that an ion irradiation-driven intermixing and disordering at the Co-Pt interfaces was inducing a reduction of the anisotropy, coercivity, and Curie temperature. In our recent paper [4] we have presented a new effect - remarkable change of a magnetic anisotropy in the Pt/Co(2.6 nm)/Pt (deposited by sputtering technique) induced by an uniform low fluence Ga+ ion irradiation at 30 keV. With increasing fluence D magnetization rotates from in-plane to out-of-plane state and then back to in-plane state. Very recently the second up-turn of the magnetization was observed at the higher irradiation fluence [5]. Low dose Ga-ion irradiation creation of out-of-plane magnetization branch is illustrated in Fig.1 Read more ...

15 - Spindynamics in CaBaCo2Fe2O7 under Strong Geometrical Frustration.

J. Reim1, L. Fritz2, M. Valldor3, W. Schweika1

1 Jülich Centre for Neutron Science (JCNS) and Peter Grünberg Institute (PGI), JARA-FIT, Forschungszentrum Jülich, 52425 Jülich, Germany
2 Institut für Theoretische Physik, Universität zu Küln, Zülpicher Straße 77, 50937 Köln, Germany
3 II. Physikalisches Institut, Universität zu Köln, D-50937 Köln, Germany

Recent studies of spin correlations in new materials belonging to the swedenborgite compound family (P63mc) [1] exhibit signs of unusual strong geometric frustration: at low temperatures, indications for quasi 2D spin correlations, spin glass or spin liquid states, and also rather complex, partly ordered ground states have been observed.[2-5] Several groups have investigated this compound family with different stoichiometry, however, up to date the main focus has been on solving structural and ground state configurations (f.e. [6]). Since the material characteristics are dominated by the strong magnetic frustration, excitations are very sensitive to small changes in ordering and exchange interactions. We will present neutron inelastic scattering on a single crystal of the compound CaBaCo2Fe2O7, that have been obtained from triple axis (PANDA) and thermal time-of-flight scattering (ARCS). The experimental results will be discussed in comparison with theoretical calculations of the phase diagram and the spin dynamics based on nearest neighbor Heisenberg models. Read more ...

16 - Pulsed magnetic field for synchrotron.

F. Duc1, X. Fabrèges1, T. Roth2,3, C. Detlefs2, P. Frings1, M. Nardone1, J. Bilette1, J. Béard1, G. L. J. A. Rikken1

1 Laboratoire National des Champs magnétiques Intenses, UPR3228 CNRS-INSA-UJF-UPS, Toulouse and Grenoble, France
2 European Synchrotron Radiation Facility, Grenoble, FRANCE
3 European XFEL, Hamburg, Germany

Over the past 10 years, efforts to combine high magnetic fields with X-ray diffraction and spectroscopy have given rise to the development of high field magnets with configurations other than simple solenoids [1-3]. In this context, pulsed magnetic fields play a central role, operating in the 30-40 T range, high above superconducting magnet.
Here, we will present the various pulsed field magnet devices jointly developed by the LNCMI-Toulouse and the ESRF, Grenoble. Details of both XMCD/XAS and diffraction setups will be presented, concomitantly with first results. Part of this research was funded by the ANR (Grant N°. ANR-05-BLAN-0238/ SySMaF). Read more ...

17 - 40 T pulsed field device for neutron experiments.

F. Duc1, J. Bilette1, J. Béard1, P. Frings1, X. Fabrèges1, X. Tonon2, B. Rollet2, E. Lelièvre-Berna2, E. Lorenzo3, L.-P. Regnault4

1 Laboratoire National des Champs magnétiques Intenses, UPR3228 CNRS-INSA-UJF-UPS, Toulouse and Grenoble, France
2 Institut Laué Langevin, Grenoble, France
3 Institut Néel, UPR2940 CNRS-UJF, Grenoble, France
4 CEA Grenoble, INAC-SPSMS-MDN,Grenoble, France

The last ten years have seen a growing interest for the combined use of pulsed high magnetic fields and synchrotron or neutron techniques. However high magnetic field experiments at large user facilities require a high duty-cycle.
Within the framework of the MAGFINS project, the High Magnetic Field National Laboratory of Toulouse (LNCMI-T) has studied, designed and built a new coil with large angle conical access and cooling channels to increase the duty-cycle. The magnet produces a horizontal field in a bi-conical geometry, ±15 and ±30° upstream and downstream of the sample, respectively, that should allow neutron beam access over a wide range of scattering angles. It should generate pulsed fields up to 40 T with a rise time of 22 ms every ~5 min using a 1.15 MJ transportable pulsed field power supply developed at the LNCMI-T. This coil will be implemented into a cryogenic environment and used for single crystal neutron diffraction experiments at the ILL. Read more ...

18 - Novel Au based rare-earth template for the growth of ultra-high dense arrays of magnetic quantum dots.

L. Fernández1, M. Ormaza3, M. Blanco1, A. Ayuela2, J. E. Ortega1,2,3, F. Schiller2

1 DIPC, Manuel de Lardizábal 4, E-20018 San Sebastián, Spain.
2 Centro de Física de Materiales (CSIC), Manuel de Lardizábal 5, E-20018 San Sebastián, Spain.
3 Departamento de Física Aplicada I, Universidad del País Vasco, Plaza de Oñate 2, E-20018 San Sebastián, Spain.

The growth of magnetic nanoparticles on surfaces by auto-organization processes represents a flexible and powerful alternative to obtain high-density, patterned magnetic storage media. Here, we report on a Au based rare-earth template and the further growth of magnetic Co dots on top with very high areal densities up to 54 Teradots/inch2 [1, 2]. The structural properties of the template and the tunability of the quantum dot array have been thoroughly explored by Scanning Tunneling Microscopy. Aditionally, the magnetic response of the nanodots has been investigated by X-ray Magnetic Circular Dichroism and Full-Potential-Linearised-Augmented-Plane-Wave, showing an antiferromagnetical coupling between the Co dots and the GdAu2 template for low Co coverage. Read more ...

19 - Investigations towards Multiferroic Layer Systems.

M. Welke1, R. K. Govind2, M. Trautmann2, J. Gräfe1, V. H. Babu1, F. Bern3 , M. Ziese3, K.-M. Schindler2, R. Denecke1

1 Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, D-04103 Leipzig
2 Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, D-06120 Halle
3 Institut für Experimentelle Physik II, Universität Leipzig, Linnéstr. 3, D-04103 Leipzig

Systems with multiferroic properties are of interest for research since the 1960s.[1] This field of research has been started with investigations of single phase multiferroics, whereas in the last decade layer systems with a ferroelectric and a ferromagnetic component are in the focus.[2] Bariumtitanate (BTO) is a typical ferroelectric compound, which is used as substrate for deposition of ferro- or ferrimagnetic layers. Co films covering the range up to 13 Å thick films have been prepared on BTO(001) by e-beam evaporation and subsequently measured using different light helicities in X-ray absorption spectroscopy (XAS). This results in X-ray magnetic circular dichroism (XMCD). There is an onset of in-plane magnetism for Cobalt at around 9 Å, accompanied by enhanced orbital moments. Using Pulsed Laser Deposition (PLD) 100 Å thick layers of Nickelferrite (NFO) and Cobaltferrite (CFO) have been prepared ex-situ and transferred for super superconducting quantum interference device (SQUID) measurements in order to obtain magnetization loops. Read more ...

20 - MBE-grown transition metal oxide thin films.

A. Steffen1, S.Pütter1, S. Mattauch1, and Th. Brückel1,2

1 Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at FRM II, Lichtenbergstr. 1, 85747 Garching
2 Jülich Centre for Neutron Science JCNS und Peter Grünberg Institut PGI, JCNS-2, PGI-4: Streumethoden, Forschungszentrum Jülich GmbH, 52425 Jülich

Transition metal oxide thin films give rise to a huge variety of fascinating phenomena like ferromagnetism at interfaces of non-magnetic materials as found in SrTiO3/KTaO3[1]. To analyze these effects quantitatively a well defined layer structure is needed to relate macroscopically gained properties to microscopic structure probed via synchrotron or neutron scattering. By molecular beam epitaxy (MBE) high quality epitaxial films can be achieved with high purity, low intrinsic defect concentrations and atomic-layer control. The stoichiometry within the films may be varied easily.
We will show first results of samples grown via oxide molecular beam epitaxy. The MBE setup is located at the FRM II and is dedicated to work as a user facility to offer the neutron and synchrotron community high quality transition metal oxide and metal heterostructures. As a first system we optimized the growth parameters for La2/3Sr1/3MnO3/SrTiO3 to compare these samples with well-established reference data from literature[2,3] and show that we achieved compareable quality. Read more ...

21 - Sublimable Spin Transition Compounds.

C. Rajnák and M. Ruben

1 Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany).
2 Université de Strasbourg, Institut de Physique et Chimie des Materiaux de Strasbourg (France).

The aim of this research project is to synthesize and study potentially sublimable six-coordinate iron(II) compounds and use of the bistable behaviour of spin transition (ST) complexes in single molecule spintronic devices. The change of the electronic configuration, between the low-spin (LS; S = 0) and high-spin (HS; S = 2) of iron Fe2+ complexes, is accompanied by interesting changes in the optical and magnetic properties. The (ST) complexes type of [Fe(L-1H)2]0 should be sublimable with UHV (Ultra-high-vacuum) method and surface investigated at the single molecule level [1, 2]. Read more ...

22 - XAS Studies on All-Oxide Ferromagnetic/Ferroelectric Heterosystems: SrTiO3(001)/La0.7Sr0.3MnO3/BaTiO3 .

H. Doǧanay1, I. Krug1, J. Schubert2, D. Gottlob1,3, F. Nickel1, and C. M. Schneider1,3

1 Peter Grünberg Institut/PGI-6, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
2 Peter Grünberg Institut/PGI-8, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
3 Fakultät für Physik, Universität Duisburg-Essen, 47048 Duisburg, Germany

The electrical control of the magnetization in multiferroics -called magnetoelectric coupling - might promote a new era of magnetoelectric memory devices. To date, there are only few compounds which are multiferroic at room temperature, and a lot of effort is put into the research for high TC materials. The solution may potentially not lie in single phase multiferroics, but in compound and layered materials, allowing a greater freedom in the design of the desired properties, i. e. high remanent magnetization and high remanent electric polarization. For instance, it is predicted by ab-initio calculations, that there is a charge redistribution at the Fe/BaTiO3 (BTO) [Sahoo, S. et al. PRB 76 (2007) 092108] interface, which is induced by the ferroelectric polarization, changing the interfacial magnetization of the ferromagnet. Read more ...

If you have any questions or comments please contact H. Bulou