Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 29: Micro- and Nanostructured Magnetic Materials

MA 29.10: Vortrag

Mittwoch, 13. März 2013, 17:30–17:45, H23

How to make La_0.7Sr_0.3MnO₃ nanostructures without losing the magnetization — •Martin Wahler¹, Bastian Büttner¹, Hans-Helmuth Blaschek¹, Nico Homonnay¹, Olga Wid¹, and Georg Schmidt^1,2 — ¹Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany — ²Interdisziplinäres Zentrum für Materialwissenschaften, Heinrich-Damerow-Str. 4, 06120 Halle, Germany

The ferromagnetic oxide La_0.7Sr_0.3MnO₃ has a high spin polarization and T_C>300 K. It is thus a good candidate for all-oxide microelectronic devices exploiting effects like the spin transfer torque and spin pumping. For state-of-the-art microelectronics applications, however, lateral dimensions are in the sub-100 nm regime and suitable patterning processes need to be developed. For ferromagnetic oxides this can be complicated. Many dry etching processes like Ar ion milling can achieve a reasonable pattern geometry, however, at the cost of a loss of magnetization in the nanostructures because of process induced defects. We have developed a process in which a resist mask is defined by e-beam lithography. Using a chlorine-based RIE step an array of about 70 million rectangles with dimensions of each approximately 100 nm times 230 nm is fabricated from a 20 nm thick LSMO layer. The magnetic properties are measured using a SQUID vibrating sample magnetometer and show no loss of magnetization compared to the unpatterned layer. Ferromagnetic resonance measurements indicate that the patterning also overcomes the built-in crystalline anisotropy of the LSMO layer. We acknowledge the support by the EU-project IFOX.