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Wu WB, Kasiuk J, Nguyen TNA, Fedotova J, Przewoźnik J, Kapusta C, Kupreeva O, Lazarouk S, Do KT, Nguyen TH, Vu HK, Vu DL, Åkerman J. Complex magnetic ordering in nanoporous [Co/Pd] 5-IrMn multilayers with perpendicular magnetic anisotropy and its impact on magnetization reversal and magnetoresistance. Phys Chem Chem Phys 2020; 22:3661-3674. [PMID: 32002524 DOI: 10.1039/c9cp05947d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have systematically investigated the magnetization reversal characteristics and magnetoresistance of continuous and nanoporous [Co/Pd]5-IrMn multilayered thin films with perpendicular magnetic anisotropy at different temperatures (4-300 K). For their nanostructuring, porosity was induced by means of deposition onto templates of anodized titania with small (∼30 nm in diameter) homogeneously distributed pores. The magnetization reversal and magnetoresistance of the porous films were found to be closely related to the splitting of the ferromagnetic material into regions with different magnetic properties, in correlation with the complex morphology of the porous system. Independent magnetization reversal is detected for these regions, and is accompanied by its strong impact on the magnetic order in the capping IrMn layer. Electron-magnon scattering is found to be a dominant mechanism of magnetoresistance, determining its almost linear field dependence in a high magnetic field and contributing to its magnetoresistance behavior, similar to magnetization reversal, in a low magnetic field. Partial rotation of IrMn magnetic moments, consistent with the magnetization reversal of the ferromagnet, is proposed as an explanation for the two-state resistance behavior observed in switching between high-resistive and low-resistive values at the magnetization reversal of the porous system studied.
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Affiliation(s)
- Wen-Bin Wu
- Institute for Nuclear Problems, Belarusian State University, 220006 Minsk, Belarus.
| | - Julia Kasiuk
- Institute for Nuclear Problems, Belarusian State University, 220006 Minsk, Belarus.
| | - Thi Ngoc Anh Nguyen
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Julia Fedotova
- Institute for Nuclear Problems, Belarusian State University, 220006 Minsk, Belarus.
| | - Janusz Przewoźnik
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Department of Solid State Physics, 30-059 Krakow, Poland
| | - Czesław Kapusta
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Department of Solid State Physics, 30-059 Krakow, Poland
| | - Olga Kupreeva
- Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus
| | - Serguei Lazarouk
- Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus
| | - Khanh Tung Do
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Thanh Huong Nguyen
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Hong Ky Vu
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Dinh Lam Vu
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Johan Åkerman
- Department of Physics, University of Gothenburg, 41296 Göteborg, Sweden
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Ho P, Tu KH, Zhang J, Sun C, Chen J, Liontos G, Ntetsikas K, Avgeropoulos A, Voyles PM, Ross CA. Domain configurations in Co/Pd and L10-FePt nanowire arrays with perpendicular magnetic anisotropy. NANOSCALE 2016; 8:5358-5367. [PMID: 26883011 DOI: 10.1039/c5nr08865h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Perpendicular magnetic anisotropy [Co/Pd]15 and L10-FePt nanowire arrays of period 63 nm with linewidths 38 nm and 27 nm and film thickness 27 nm and 20 nm respectively were fabricated using a self-assembled PS-b-PDMS diblock copolymer film as a lithographic mask. The wires are predicted to support Néel walls in the Co/Pd and Bloch walls in the FePt. Magnetostatic interactions from nearest neighbor nanowires promote a ground state configuration consisting of alternating up and down magnetization in adjacent wires. This was observed over ∼75% of the Co/Pd wires after ac-demagnetization but was less prevalent in the FePt because the ratio of interaction field to switching field was much smaller. Interactions also led to correlations in the domain wall positions in adjacent Co/Pd nanowires. The reversal process was characterized by nucleation of reverse domains, followed at higher fields by propagation of the domains along the nanowires. These narrow wires provide model system for exploring domain wall structure and dynamics in perpendicular anisotropy systems.
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Affiliation(s)
- Pin Ho
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA02139, USA.
| | - Kun-Hua Tu
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA02139, USA.
| | - Jinshuo Zhang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA02139, USA.
| | - Congli Sun
- Department of Materials Science and Engineering, University of Wisconsin, Madison, WI53706, USA
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, Singapore 119077, Singapore
| | - George Liontos
- Department of Materials Science and Engineering, University of Ioannina, University Campus - Dourouti, Ioannina 45110, Greece
| | - Konstantinos Ntetsikas
- Department of Materials Science and Engineering, University of Ioannina, University Campus - Dourouti, Ioannina 45110, Greece
| | - Apostolos Avgeropoulos
- Department of Materials Science and Engineering, University of Ioannina, University Campus - Dourouti, Ioannina 45110, Greece
| | - Paul M Voyles
- Department of Materials Science and Engineering, University of Wisconsin, Madison, WI53706, USA
| | - Caroline A Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA02139, USA.
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Kishine JI, Proskurin IV, Ovchinnikov AS. Tuning magnetotransport through a magnetic kink crystal in a chiral helimagnet. PHYSICAL REVIEW LETTERS 2011; 107:017205. [PMID: 21797570 DOI: 10.1103/physrevlett.107.017205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Indexed: 05/31/2023]
Abstract
We consider magnetotransport properties in a conducting chiral helimagnet, where the magnetic kink crystal (MKC) is formed under weak magnetic field applied perpendicular to the helical axis. The MKC behaves as a magnetic superlattice potential and results in Bragg scattering of conduction electrons. Tuning of the weak magnetic field enables us to control the size of the superlattice Brillouin zone and gives rise to a series of divergent resistivity anomalies originating from resonant Bragg scatterings. We discuss as well a nontrivial magnetic structure in the resonant states realized in the subsystem of the itinerant electrons.
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Affiliation(s)
- Jun-ichiro Kishine
- Department of Basic Sciences, Kyushu Institute of Technology, Kitakyushu, Japan
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Kobs A, Hesse S, Kreuzpaintner W, Winkler G, Lott D, Weinberger P, Schreyer A, Oepen HP. Anisotropic interface magnetoresistance in Pt/Co/Pt sandwiches. PHYSICAL REVIEW LETTERS 2011; 106:217207. [PMID: 21699340 DOI: 10.1103/physrevlett.106.217207] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 03/24/2011] [Indexed: 05/31/2023]
Abstract
We report on an effect of reduced dimensionality on the magnetotransport in cobalt layers sandwiched by platinum. In a current in-plane geometry it is found that the resistivity depends on the magnetization orientation within the plane perpendicular to the current direction. The resistivity shows a symmetry adapted cos(2) dependence on the angle to the surface normal, with the maximum along the surface normal. The Co thickness dependence of the effect in Pt/Co/Pt sandwiches clearly points out that the mechanism behind this effect originates at the Co/Pt interfaces and is disparate to the texture induced geometrical size effect.
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Affiliation(s)
- A Kobs
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany
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Stickler D, Frömter R, Li W, Kobs A, Oepen HP. Integrated setup for the fabrication and measurement of magnetoresistive nanoconstrictions in ultrahigh vacuum. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:103901. [PMID: 19044723 DOI: 10.1063/1.2981693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A UHV instrument is presented for in situ fabrication of nanostructures and in situ investigation of their magnetoresistance. Nanostructures of diverse shape and size are created from thin films utilizing a focused ion beam. The magnetic nanostructures are contacted via a micromanipulator, which makes it possible to address the individual structures. The system is additionally equipped with a scanning electron microscope column, which is used for damage-free navigation and control of the structuring and contacting. First magnetoresistance measurements of structures carved into a Permalloy film demonstrate the high sensitivity and the flexibility of the new setup.
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Affiliation(s)
- Daniel Stickler
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg, Germany.
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