Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 72: [MA] Joint Session "Surface Magnetism III" (jointly with O)

O 72.5: Vortrag

Donnerstag, 29. März 2012, 16:15–16:30, BH 243

Interfacial uniaxial anisotropy and magnetization reversal of Fe/BaTiO₃(001) layers — •Vasili Hari Babu¹, Remya Kunjuveettil Govind², Joachim Gräfe¹, Martin Welke¹, Karl-Michael Schindler², and Reinhard Denecke¹ — ¹Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Germany — ²Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Germany

Multiferroics, consisting of both ferroelectric and ferromagnetic phases, have attracted scientific and technological interest due to the magnetoelectric coupling between the phases. In these heterostructures, the growth and magnetic anisotropy of the ferromagnetic phase are to be known to exploit the sizeable magnetoelectric effects. In the present work, Fe films were grown up to 24 ML thickness on a ferroelectric BaTiO₃(001) substrate by electron beam evaporation in an ultra high vacuum chamber and the determination of the magnetic properties was carried out by using in-situ magneto-optic Kerr effect. The layers were seen to have onset of ferromagnetic ordering at 6 ML thickness and the layers up to 12 ML thick were seen to exhibit uniaxial magnetic anisotropy (UMA) in the Fe[110] direction. However, the magnetization reversal of layers above 16 ML thick was seen to exhibit a growing cubic anisotropy along with the UMA from the fact that the growth of Fe(10) unit cell is 45^∘ rotated to the BaTiO₃(10) direction in order to reduce the lattice mismatch. The competition between the uniaxial (aided by the interface) and cubic anisotropies of these layers is explained by accounting the quadratic magneto-optic Kerr effects.