Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 30: Magnetic Semiconductors I
MA 30.7: Vortrag
Mittwoch, 16. März 2011, 12:30–12:45, HSZ 401
Optical studies of magnetic field induced phenomena in MBE grown MnS layer — •Manuel Demper1, Christine Bradford2, Kevin A. Prior2, and Wolfram Heimbrodt1 — 1Department of Physics and Material Science Center, Philipps University, Marburg, Germany — 2School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
Recently, a considerable amount of attention has been paid to the theoretical investigation of two-dimensional spin systems. Experimentally it is still a challenge to approach the two dimensional limit, as in reality one is always faced with quasi 2D magnetic structure. To reach the 2D limit antiferromagnetic zinc blende MnS films with various thicknesses have been prepared by MBE. To avoid any interplane interactions these single layers were grown in between diamagnetic ZnSe cladding layers on a GaAs substrate. Since the small number of spins in these single layers makes conventional techniques like SQUID-measurements rather difficult, we developed an optical spectroscopy method using the internal 4T1-6A1 emission of the Mn 3d-states as a probe. Thus, the MnS films have been studied by temperature dependent photoluminescence measurements in external magnetic fields up to 7 T. The detailed studies of the data reveal a phase diagram for the thinnest sample, which is known from antiferromagnetic materials with a weak uniaxial anisotropy. However, for a thick MnS layer no effect on the antiferromagnetic phase was observed. We will present a detailed explanation of this unique magnetic behavior.