--- _id: '635' abstract: - lang: eng text: Magnetic vortex structures are of high technological relevance due to their possible application in magnetic memory. Moreover, investigating magnetization reversal via vortex formation is an important topic in basic research. Typically, such vortices are only investigated in homogeneous magnetic materials of diverse shapes. Here, we report for the first time on micromagnetic simulation of vortex formation in magnetic bow-tie nanostructures, comprising alternating parts from iron and permalloy, investigated for two different thicknesses and under different angles of the external magnetic field. While no vortex was found in pure permalloy square, nanoparticles of the dimensions investigated in this study and in case of iron only a relatively thick sample allowed for vortex formation, different numbers of vortices and antivortices were found in the bow-tie structures prepared from both materials, depending on the angular field orientation and the sample thickness. By stabilizing more than one vortex in a confined nanostructure, it is possible to store more than one bit of information in it. Our micromagnetic simulations reveal that such bi-material structures are highly relevant not only for basic research, but also for data storage applications. article_number: '5' article_type: original author: - first_name: Devika full_name: Sudsom, Devika last_name: Sudsom - first_name: Irén full_name: Juhász Junger, Irén last_name: Juhász Junger - first_name: Christoph full_name: Döpke, Christoph last_name: Döpke - first_name: Tomasz full_name: Blachowicz, Tomasz last_name: Blachowicz - first_name: Lothar full_name: Hahn, Lothar last_name: Hahn - first_name: Andrea full_name: Ehrmann, Andrea id: '223776' last_name: Ehrmann orcid: 0000-0003-0695-3905 citation: alphadin: 'Sudsom, Devika ; Juhász Junger, Irén ; Döpke, Christoph ; Blachowicz, Tomasz ; Hahn, Lothar ; Ehrmann, Andrea: Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures. In: Condensed Matter Bd. 5 (2020), Nr. 1' ama: Sudsom D, Juhász Junger I, Döpke C, Blachowicz T, Hahn L, Ehrmann A. Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures. Condensed Matter. 2020;5(1). doi:10.3390/condmat5010005 apa: Sudsom, D., Juhász Junger, I., Döpke, C., Blachowicz, T., Hahn, L., & Ehrmann, A. (2020). Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures. Condensed Matter, 5(1). https://doi.org/10.3390/condmat5010005 bibtex: '@article{Sudsom_Juhász Junger_Döpke_Blachowicz_Hahn_Ehrmann_2020, title={Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures}, volume={5}, DOI={10.3390/condmat5010005}, number={15}, journal={Condensed Matter}, author={Sudsom, Devika and Juhász Junger, Irén and Döpke, Christoph and Blachowicz, Tomasz and Hahn, Lothar and Ehrmann, Andrea}, year={2020} }' chicago: Sudsom, Devika, Irén Juhász Junger, Christoph Döpke, Tomasz Blachowicz, Lothar Hahn, and Andrea Ehrmann. “Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures.” Condensed Matter 5, no. 1 (2020). https://doi.org/10.3390/condmat5010005. ieee: D. Sudsom, I. Juhász Junger, C. Döpke, T. Blachowicz, L. Hahn, and A. Ehrmann, “Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures,” Condensed Matter, vol. 5, no. 1, 2020. mla: Sudsom, Devika, et al. “Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures.” Condensed Matter, vol. 5, no. 1, 5, 2020, doi:10.3390/condmat5010005. short: D. Sudsom, I. Juhász Junger, C. Döpke, T. Blachowicz, L. Hahn, A. Ehrmann, Condensed Matter 5 (2020). date_created: 2021-01-03T14:42:18Z date_updated: 2021-05-19T14:01:34Z ddc: - '530' department: - _id: '103' doi: 10.3390/condmat5010005 file: - access_level: open_access content_type: application/pdf creator: aehrmann date_created: 2021-01-03T14:41:31Z date_updated: 2021-01-03T14:41:31Z file_id: '636' file_name: _2020_Sudsom_CondMatter5_5_corr.pdf file_size: 4886370 relation: main_file success: 1 file_date_updated: 2021-01-03T14:41:31Z funded_apc: '1' has_accepted_license: '1' intvolume: ' 5' issue: '1' keyword: - magnetic nanostructures - micromagnetic simulation - bow-tie structure - vortex - magnetization reversal - iron - permalloy - lithography language: - iso: eng oa: '1' publication: Condensed Matter publication_identifier: issn: - 2410-3896 publication_status: published quality_controlled: '1' status: public title: Micromagnetic Simulation of Vortex Development in Magnetic Bi-Material Bow-Tie Structures type: journal_article user_id: '237837' volume: 5 year: '2020' ... --- _id: '678' abstract: - lang: eng text: Asymmetric magnetic hysteresis loops are usually found in exchange bias (EB) systems, typically after field cooling a system below the Néel temperature of an antiferromagnet exchange coupled to a ferromagnet. Alternatively, asymmetric hysteresis loops may occur due to undetected minor loops or in systems with a rotational anisotropy. Here, we report on an exchange bias thin film system MgO(100)/Co/CoO, examined at room temperature, which is far above the blocking temperature, by the magneto-optical Kerr effect (MOKE). While the longitudinal hysteresis loops partly show steps which are well-known from diverse purely ferromagnetic systems, the transverse hysteresis loops exhibit clear asymmetries, similar to exchange biased systems at low temperatures, and unusual transverse magnetization values at saturation. Since minor loops and a rotational anisotropy can be excluded in this case, this asymmetry can possibly be a residue of the exchange bias coupling at lower temperatures. article_number: '71' article_type: original author: - first_name: Andrea full_name: Ehrmann, Andrea last_name: Ehrmann - first_name: Tomasz full_name: Blachowicz, Tomasz last_name: Blachowicz date_created: 2021-01-03T17:47:40Z date_updated: 2021-01-18T15:32:28Z ddc: - '620' department: - _id: '103' doi: 10.3390/condmat5040071 file: - access_level: open_access content_type: application/pdf creator: aehrmann date_created: 2021-01-03T17:47:11Z date_updated: 2021-01-03T17:47:11Z file_id: '679' file_name: _2020_Ehrmann_CondensMatter05_71v2.pdf file_size: 1118449 relation: main_file success: 1 file_date_updated: 2021-01-03T17:47:11Z has_accepted_license: '1' intvolume: ' 5' issue: '4' keyword: - exchange bias - rotatable anisotropy - blocking temperature - minor loops - Co/CoO language: - iso: eng oa: '1' publication: Condensed Matter publication_identifier: issn: - 2410-3896 publication_status: published quality_controlled: '1' status: public title: Asymmetric Hysteresis Loops in Co Thin Films type: journal_article user_id: '223776' volume: 5 year: '2020' ...