Title :
Magneto-Electric Control of Surface Anisotropy and Nucleation Modes in L1
-CoPt Thin Films
Author :
Manchanda, Priyanka ; Kumar, Pranaw ; Fangohr, Hans ; Sellmyer, David J. ; Kashyap, Arti ; Skomski, Ralph
Author_Institution :
Dept. of Phys. & Astron., Univ. of Nebraska, Lincoln, NE, USA
Abstract :
The interplay between electric field-controlled surface magnetic anisotropy and micromagnetic nucleation modes for L10-CoPt thin films is investigated with density-functional and micromagnetic model calculations. The electric field redistributes electron states near the Fermi level, which has a fairly strong effect on the surface anisotropy, but due to inversion symmetry, the net anisotropy of the films with odd numbers of layers remains unchanged. By contrast, the micromagnetic nucleation mode is spatially asymmetric even for symmetric thin films with odd numbers of layers. This leads to a reduction of the nucleation field (coercivity) and-for suitably chosen nanostructures-to substantial changes in the hysteretic behavior. In the lowest order, the coercivity reduction is independent of the total film thickness. This counterintuitive feature can potentially be exploited in magneto-electric switching devices.
Keywords :
Fermi level; cobalt alloys; coercive force; density functional theory; magnetic anisotropy; magnetic hysteresis; magnetic thin films; metallic thin films; micromagnetics; nanostructured materials; nucleation; platinum alloys; surface states; CoPt; Fermi level; L10-CoPt thin films; coercivity reduction; density-functional model calculations; electric field-controlled surface magnetic anisotropy; electron states; hysteretic behavior; inversion symmetry; magnetoelectric control; magnetoelectric switching devices; micromagnetic model calculations; micromagnetic nucleation modes; nucleation field; symmetric thin films; Anisotropic magnetoresistance; Electric fields; Films; Micromagnetics; Perpendicular magnetic anisotropy; Magneto-electronics; thin films; thin-films;
Journal_Title :
Magnetics Letters, IEEE
DOI :
10.1109/LMAG.2014.2360159