Funding source: Executive Unit for Financing Higher Education, Research, Development and Innovation (UEFISCDI)
Funding scheme: EXPLORATORY RESEARCH PROJECTS - PN-II-ID-PCE-2012-4
Project code: PN-II-ID-PCE-2012-4-0424
Contract number: 46/2013
Project title: Theoretical Modeling of the Magnetic Behavior of Rapidly Solidified Ferromagnetic Amorphous Submicron Wires and Nanowires
Project duration: September 2013 – December 2016
Total budget: 1,115,000 RON

Project summary: The main objective of this project is to develop a comprehensive model for the description of the magnetic behavior of rapidly solidified ferromagnetic amorphous nanowires and submicron wires and for the interpretation of the experiments performed on these novel materials.

This main objective envisages two main directions:

1. the analytical modeling of their magnetic domain structures and magnetic anisotropy distributions; and
2. the numerical simulation of the magnetic hysteresis loops in the rapidly solidified amorphous nanowires and submicron wires.

An associate objective is the experimental verification of the achieved analytical and numerical models.

All these goals are feasible and can be reached with the current expertise, qualified human resources and suitable research infrastructure which are currently available at the National Institute of Research and Development for Technical Physics.

Research team:

The research team consists of the Project Director – Dr. Tibor-Adrian Óvári, three Senior Scientists with extensive experience in the topic of the project – Prof. Dr. Horia Chiriac, Dr. Firuta Borza and Dr. Maria Urse, three postdoctoral researchers - Dr. Sorin Corodeanu, Dr. Cristian Rotarescu and Dr. Mihai Tibu, one PhD student - Ms. Alina Damian, and one engineer - Mr. Costica Hlenschi.

Expected results: We aim to develop for the first time a comprehensive and coherent theoretical framework in which all the existing and future experimental results on rapidly solidified amorphous submicron wires and nanowires will be explained. This framework will become an essential tool for scientists and engineers, and will contribute decisively to the analysis and control of the application-related phenomena in the rapidly solidified amorphous submicron wires and nanowires. The envisaged results will be new and will make an important contribution in magnetism and magnetic materials.

Reports:

2013: Calculation of the radial distribution of internal stresses induced during the rapid solidification of the amorphous glass-coated nanowires and submicron wires having various dimensions (metallic nucleus between 50 and 950 nanometers and glass coating thickness between 1 and 20 microns).

2014: Analytical calculation of the magnetoelastic and magnetostatic terms in amorphous glass-coated nanowires and submicron wires prepared by rapid solidification methods, having various dimensions and compositions. Impact on the domain structure formation and magnetic anisotropy distribution. Link to 2014 report (in Romanian) – this report covers both 2013 and 2014.

2015: Numerical simulation of the magnetic hysteresis in rapidly solidified amorphous glass-coated nanowires and submicron wires with various compositions and dimensions. Link to 2015 report (in Romanian).

2016: Optimization of the micromagnetic simulation code and experimental verification of the calculated results (inductive and MOKE hysteresis loop measurements, FMR investigations, domain wall velocity measurements). Final Progress Report 2013 - 2016 (in English).

Publications:

1. T.-A. Óvári and H. Chiriac, Intrinsic domain wall pinning in rapidly solidified amorphous nanowires, J. Appl. Phys. 115 (2014) 17A329.
2. T.-A. Óvári, N. Lupu, S. Corodeanu, and H. Chiriac, Magnetostatic and magnetoelastic interactions in glass-coated magnetostrictive nanowires, IEEE Trans. Magn. 50 (2014) 2006904, DOI: 10.1109/TMAG.2014.2320301.
3. T.-A. Óvári and H. Chiriac, Origin of magnetic bistability in rapidly solidified (Co_0.94Fe_0.06)_72.5Si_12.5B₁₅ nearly zero magnetostrictive amorphous nanowires, J. Appl. Phys. (2015) 17D502, DOI: 10.1063/1.4906298.
4. T.-A. Óvári, S. Corodeanu, C. Rotarescu, and H. Chiriac, Magnetization reversal in zero-magnetostrictive rapidly solidified amorphous nanowires, IEEE Trans. Magn. (2014) 2007304, DOI: 10.1109/TMAG.2014.2325131.
5. C. Rotarescu, A. Atitoaie, L. Stoleriu, T.-A Óvári, N. Lupu, H. Chiriac, Shape anisotropy in zero-magnetostrictive rapidly solidified amorphous nanowires, Physica B-Condensed Matter, vol. 486, pp. 73 -76 (2016).
6. T.-A. Óvári, C. Rotarescu, A. Atitoaie, S. Corodeanu, N. Lupu, H. Chiriac, Magnetic anisotropy in rapidly quenched amorphous glass-coated nanowires, J. Magn. Magn. Mater., vol. 410, pp. 100-104 (2016).
7. M. Tibu, M. Lostun, D.A. Allwood, C. Rotarescu, A. Atitoaie, N. Lupu, T.-A Óvári, H. Chiriac, Controlled motion of domain walls in submicron amorphous wires, AIP Advances, vol. 6 055922 (2016).
8. H. Chiriac, N. Lupu, G. Stoian, S. Corodeanu, T.-A Óvári, Ultrathin nanocrystalline magnetic wires, Crystals, submitted (Dec. 2016).

Book Chapter: T.-A. Óvári, N. Lupu, and H. Chiriac, “Magnetic nanowires and submicron wires prepared by quenching and drawing technique”, Chapter 7 in MAGNETIC NANO- AND MICROWIRES: DESIGN, SYNTHESIS, PROPERTIES AND APPLICATIONS (Edited by M. Vázquez), Woodhead Publishing, 2015, pp. 199-223, ISBN 978-0-08-100164-6.

Conference participations:

1. 58th Annual Magnetism & Magnetic Materials Conference, Denver, Colorado, U.S.A., November 2013 – 1 presentation.
2. 2014 Intermag Europe – The IEEE International Magnetics Conference, Dresden, Germany, May 2014 – 2 presentations.
3. 10th European Magnetic Sensors and Actuators Conference – EMSA 2014, Vienna, Austria, July 2014 – 1 presentation.
4. 59th Annual Magnetism & Magnetic Materials Conference, Honolulu, Hawaii, U.S.A., November 2014 – 1 presentation.
5. IEEE International Magnetics Conference – INTERMAG 2015, Beijing, China, May 2015 – 2 presentations.
6. 20th International Conference on Magnetism – ICM 2015, Barcelona, Spain, July 2015 – 1 presentation.
7. IOP (Institute of Physics) Magnetism 2015, Leeds, United Kingdom, March 2015 – 1 presentation.
8. 10th International Symposium on Hysteresis Modeling and Micromagnetics – HMM 2015, Iasi, Romania, May 2015 – 1 presentation.
9. 7th International Workshop on Amorphous and Nanostructured Magnetic Materials – ANMM’2015, Iasi, Romania, September 2015 – 2 presentations.
10. 8th Joint European Magnetics Symposia (JEMS) - JEMS 2016, Glasgow, United Kingdom, 21 - 26 August 2016 - 2 presentations.
11. 16th Czech and Slovak Conference of Magnetism - CSMAG'16, Kosice, Slovakia, 13 - 17 June 2016 1 presentation.
12. 61st Annual Conference of Magnetism and Magnetic Materials - MMM 2016, New Orleans, Louisiana, United States, 31 October - 4 November 2016 - 1 presentation.
13. 13th Joint MMM-Intermag Conference, San Diego, California, 11 - 15 January 2016 - 1 presentation.

Contact details:

Dr. Tibor-Adrian Óvári
National Institute of Research and Development for Technical Physics
47 Mangeron Boulevard, 700050 Iasi
Email: taovari [at] phys-iasi.ro
Tel: 0232-430680 ext. 241
Fax: 0232-231132