SWR Studies of Higher-Order Surface Anisotropy Terms in (Ga,Mn)As Thin Films

H. Puszkarskia, P. Tomczakb and H.T. Diepc aSurface Physics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland, bQuantum Physics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland cLaboratoire de Physique Theéorique et Modélisation, Université de Cergy-Pontoise, CNRS, UMR 8089, 2, Av. Adolphe Chauvin, 95302 Cergy-Pontoise Cedex, France

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We extend the theory of spin-wave resonance (SWR) by introducing a new formula representing the surface pinning parameter as a series of contributions from different anisotropies existing in (Ga,Mn)As thin films. Comparing our theory with the reported experimental studies of SWR in thin films of the ferromagnetic semiconductor (Ga,Mn)As, we find that besides the first-order cubic anisotropy, higher-order cubic anisotropies (in the second and third orders) as well as uniaxial anisotropies (perpendicular in the first and second orders, and in-plane diagonal) occur on the surface of this material. To our best knowledge this is the first report of the existence of higher-order surface anisotropy fields in (Ga,Mn)As thin films.

DOI: 10.12693/APhysPolA.133.635 PACS numbers: 75.50.Pp, 76.50.+g, 75.70.-i, 75.30.Ds, 76.60.-k