Anisotropy engineering of soft thin films in the undulated magnetic state

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:514

Article

Sanchez, Elena H.^1,2  Rodriguez-Rodriguez, Gabriel^1,2  Aragon, Rodrigo^1,2  Arranz, Miguel A.³  Rebollar, Esther⁴  Castillejo, Marta⁴  Colino, Jose M.^1,2 

[1] Univ Castilla La Mancha, Inst Nanociencia Nanotecnol & Mat Mol, Campus Fabrica de Armas, Toledo 45071, Spain

[2] Univ Castilla La Mancha, Dept Fis Aplicada, Campus Fabrica de Armas, Toledo 45071, Spain

[3] Univ Castilla La Mancha, Fac Ciencias & Tecnol Quim Ciudad Real, Ciudad Real 13071, Spain

[4] CSIC, Inst Quim Fis Rocasolano, Serrano 119, Madrid 28006, Spain

关键词: Laser induced periodic surface structures;    Magnetic thin films;    Sputtering;    Uniaxial magnetic anisotropy;    Magneto-optical effects;   

DOI  :  10.1016/j.jmmm.2020.167149

来源: Elsevier

【 摘 要 】

Advanced materials often involve multi-dependent approaches, merging electrical, optical and magnetic responses in nanostructured systems. To this purpose we have explored a semi-transparent, soft magnetic thin film (Permalloy) of nano-undulated morphology with which uniaxial anisotropy can be induced and tuned. This media is grown on the ripple surface of flexible, polymeric foil of polyethylene terephthalate (PET) that was previously patterned by a versatile pulsed-laser irradiation technique achieving a linear array with periodicity 220-250 nm and large amplitudes around 45 nm. Vectorial Kerr (reflection) as well as Voight (transmission) magneto-optical effects confirm a complete uniaxial anisotropy induced with easy axis along the ripple pattern for Py films of thickness ranging from 10 to 30 nm. Analysis of curved magnetic systems is a major challenge, so we need to combine measurements of surface magnetization with thorough micromagnetic modelling of a quasi infinite ripple film (same dimensions as the media). Remarkably, our modelling indicates unique features confirmed by experiments; namely, two disparate demagnetizing fields in hard axis magnetization and a distinctive thickness evolution. These findings are characteristic of an undulated magnetic state with the uniaxial anisotropy driven by volume-like poles. The choice of large pattern dimensions has made possible to realize the undulated state where the anisotropy strength can simply be tuned with film thickness without any role of surface contributions. This approach to anisotropy engineering provides ground for applications design without the limitations of surface preparation.

【 授权许可】

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