Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 17: Magnetic Particles and Clusters (jointly with CPP, BP)
MA 17.3: Vortrag
Dienstag, 12. März 2013, 10:30–10:45, H22
Influence of the local atomic structure on the magnetic properties of particulate FePt-X films — •S. Wicht1,2, V. Neu1, L. Schultz1,2, O. Mosendz3, G. Parker3, D. Weller3, and B. Rellinghaus1 — 1IFW Dresden, P.O. Box 260116, D-01171 Dresden, Germany. — 2TU Dresden, IFWW, D-01062 Dresden, Germany. — 3HGST, 3403 Yerba Buena Rd, San Jose, CA-95135, USA.
FePt-nanoparticles are a promising materials candidate for recording media aiming at storage densities beyond 1 Tbit/in2. High-resolution electron microscopy (HRTEM) and vibrating sample magnetometry (VSM) are used to correlate the structural and magnetic properties of highly textured particulate films of matrix-isolated L10 ordered FePt-X (X: Cu/Ag). Particle size distributions and orientations of the particles’ magnetic easy axes with respect to their MgO seed crystals and the substrate plane are determined from planview and cross-sectional HRTEM. The texture spread of the [001] easy axes is found to be roughly 3o and clearly larger than the misalignment of the MgO crystals. Atomically resolved characterization of the FePt-X/MgO interfaces shows that this discrepancy is due to the nucleation of the FePt-X growth at MgO step edges. In accordance with the structural data, remanence measurements reveal only a weak dipolar coupling among the spatially separated FePt-X nanomagnets, and the anisotropy fields of the films are µ0 HA = 8−9 T. Surprisingly, the magnetic texture width as determined from an analysis of the hard axis magnetization curves is found to be one order of magnitude larger than the texture spread of the [001] axes. Possible origins of this finding are discussed.