2016 Publications

Torque magnetometry of perpendicular anisotropy exchange-spring heterostructures” P. Vallobra, T. Hauet, F. Montaigne, E.G Shipton, E.E. Fullerton, S. Mangin, J. Appl. Phys. 120, 013903 (2016)
Up to now, torque magnetometry has been mostly used for studying the magnetic properties of single system. Here we used it to characterize the magnetic configurations under field of a multilayer thin film, namely [Co/Pd]15 /TbFeCo exchange-spring system. The experimental results are compared to a 1D micromagnetic simulation. The good agreement between experiments and simulations allows us to deduce the evolution of the in-depth magnetic configuration as a function of the applied field orientation and amplitude. The chirality transition of the interfacial domain wall developing in the structure can also be determined with this technique.

Reproducible formation of single magnetic bubbles in an array of patterned dots” T. Liu, V. Puliafito, F. Montaigne, S. Petit, C. Deranlot, S. Andrieu, O. Ozatay, G. Finocchio and T. Hauet, J. Phys. D: Appl. Phys. 49, 245002 (2016)
Here we study the nucleation of magnetic bubble in arrays of nano- and micro-patterned dots The formation conditions of single magnetic bubbles through in-plane field demagnetization are investigated in an array of Co/Ni circular dots by magnetic force microscopy and compared to micromagnetic calculations. We demonstrate high success rates in nucleating stable bubbles.

Transport and magnetic measurements on Bi2Sr2CaCu2O8 nanowire networks prepared via electrospinning”, M.R. Koblischka, X.L. Zeng, T. Karwoth, T. Hauet, U. Hartmann, IEEE Trans. Appl. Superconductivity 26, 1800605 (2016)
Superconducting nanowire networks of Bi2Sr2CaCu2O8 (Bi-2212) were fabricated by means of the electrospinning technique. The electrospinning technique enables the growth of long nanowires up to the millimeter range, whereas the diameter of the nanowires can be controlled by the processing parameters. The resulting materials are fabric-like structures of about 4 × 4 mm2 in size, showing a large number of interconnects and junctions between the nanowires. The resulting nanowires are of granular nature with a grain size similar to the wire thickness of about 100–150 nm, and the diameter of the nanowires is about 100–200 nm as determined by electron microscopy. As these nanowire networks are a new class of superconducting materials, we studied the electric transport properties (resistance, U/I characteristics) of such nanowire networks in applied magnetic fields (0–12 T), as well as measurements of the susceptibility and magnetization hysteresis loops were performed by SQUID magnetometry.