Crystalline anisotropic magnetoresistance with two-fold and eight-fold symmetry in (In,Fe)As ferromagnetic semiconductor Appl. Phys. Lett. 100, 262409 (2012) Charge order suppression, emergence of ferromagnetism and absence of exchange bias effect in Bi0.25Ca0.75MnO3 nanoparticles: Electron paramagnetic resonance and magnetization studies J. Appl. Phys. 111, 123913 (2012) Vacancy mediated room temperature ferromagnetism in Co-doped Dy2O3 Appl. Phys. Lett. 100, 252411 (2012) Synthesis and characterization of Co2FeAl nanowires J. Appl. Phys. 111, 123906 (2012) Synthesis, structure, and magnetic behavior of nanoparticles of cubic ZnMnO3

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Équipe 101 : Nanomagnétisme et électronique de spinInternational audienceWe fabricated a perpendicularly magnetized bit pattern media using a hexagonally close-packed auto-assembled anodic alumina template with 100 nm and 50 nm periods by depositing a Co/Pt multilayer to form an ordered array of ferromagnetic nanodots, so-called nanobumps. We used Hall resistance measurements and magnetic force microscopy to characterize the dot-by-dot magnetization reversal mechanism under applied field. The role of interdot exchange coupling and dipolar coupling are investigated. Then we focus on separating the various origins of switching field distribution (SFD) in this system, namely dipolar interactions, intrinsic anisotropy distribution, and template packing faults. Finally we discuss the influence of triangular dipolar frustrations on the energy stability of demagnetized and half-switched states based on an Ising model, including local exchange coupling. The impact of SFD and lattice defects lines between misoriented ordered domains on the magnetic configurations is studied in detail

International audienceIn a recent letter, it has been predicted within first principle studies that Mn-doped ZrO2 compounds could be good candidates for spintronics application because expected to exhibit ferromagnetism far beyond room temperature. Our purpose is to address this issue experimentally for Mn-doped tetragonal zirconia. We have prepared polycrystalline samples of Y0.15(Zr0.85−yMny)O2 (y = 0, 0.05, 0.10, 0.15, 0.20) by using standard solid state method at equilibrium. The obtained samples were carefully characterized by using x-ray diffraction, scanning electron microscopy, elemental color mapping, x-ray photoemission spectroscopy, and magnetization measurements. From the detailed structural analyses, we have observed that the 5% Mn doped compound crystallized into two symmetries (dominating tetragonal and monoclinic), whereas higher Mn doped compounds are found to be in the tetragonal symmetry only. The spectral splitting of the Mn 3s core-level x-rayphotoelectron spectra confirms that Mn ions are in the Mn3+oxidation state and indicate a local magnetic moment of about 4.5 μ B/Mn. Magnetic measurements showed that compounds up to 10% of Mn doping are paramagnetic with antiferromagnetic interactions. However, higher Mn doped compound exhibits local ferrimagnetic ordering. Thus, no ferromagnetism has been observed for all Mn-doped tetragonal ZrO2 samples