Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 30: Surface Magnetism (joint session O/MA)

O 30.6: Vortrag

Dienstag, 2. April 2019, 11:45–12:00, H37

Magnetic order in Nd(0001): a new type of spin glass? — •Umut Kamber, Andreas Eich, Nadine Hauptmann, Daniel Wegner, and Alexander A. Khajetoorians — Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands

Lanthanide metals can exhibit complex magnetic structures, e.g. helical/conical spin spirals or linear spin waves. Neodymium (Nd) shows the most complicated behavior exhibiting several magnetic phase transitions below TN = 19.9 K, resulting in multi-q order according to interpretations based on magnetic neutron or X-ray diffraction experiments [1]. However, as these techniques lack spatial resolution, the variations in magnetic properties of Nd at the atomic length scale are unexplored. The local surface electronic structure of Nd(0001) has been studied only using spin-integrated STS [2,3]. Here, we present ultra-low temperature SP-STM measurements of bulk-like Nd(0001) films grown on W(110). We observe multi-q magnetic behavior on the surface as evidenced by strong short-range order, but without the existence of long-range order. Magnetic field and temperature-dependent measurements reveal high sensitivity of the spectral weight of q-states to applied fields, without any clear unique ground state, as well as evidence of aging behavior in the magnetic state. We discuss our findings in the context of unconventional spin-glass behavior. [1] R. M. Moon & R. M. Nicklow, J. Magn. Magn. Mater. 100, 139 (1991). [2] D. Wegner et al., Phys. Rev. B 73, 165415 (2006). [3] D. Wegner et al., Jpn. J. Appl. Phys. 45, 1941 (2006).