Change in Magnetic Anisotropy at the Surface and in the Bulk of FINEMET Induced by Swift Heavy Ion Irradiation

57 Fe transmission and conversion electron Mössbauer spectroscopy as well as XRD were used to study the effect of swift heavy ion irradiation on stress-annealed FINEMET samples with a composition of Fe73.5 Si13.5 Nb3 B9 Cu1. The XRD of the samples indicated changes neither in the crystal structure nor in the texture of irradiated ribbons as compared to those of non-irradiated ones. However, changes in the magnetic anisotropy both in the bulk as well as at the surface of the FINEMET alloy ribbons irradiated by 160 MeV132 Xe ions with a fluence of 1013 ion cm−2 were revealed via the decrease in relative areas of the second and fifth lines of the magnetic sextets in the corresponding Mössbauer spectra. The irradiation-induced change in the magnetic anisotropy in the bulk was found to be similar or somewhat higher than that at the surface. The results are discussed in terms of the defects produced by irradiation and corresponding changes in the orientation of spins depending on the direction of the stress generated around these defects. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.CZ-11/2007, MEB040806; Ministry of Education and Science of the Russian Federation, Minobrnauka: FEUZ-2020-0060; Hungarian Scientific Research Fund, OTKA: K100424, K115784, K115913, K43687, K68135; Joint Institute for Nuclear Research, JINR; Univerzita Palackého v Olomouci: CZ.02.1.01/0.0/0.0/17_049/0008408, IGA_PrF_2022_003, IGA_PrF_2022_013; Ural Federal University, UrFU: 04-5-1131-2017/2021; Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIHFunding: The research was supported by grants from the Hungarian National Research, Development and Innovation Office (OTKA projects No K43687, K68135, K100424, K115913, K115784) and by the Czech-Hungarian Intergovernmental Fund, Grant No. CZ-11/2007 (MEB040806). M.I.O. was supported by the Ministry of Science and Higher Education of the Russian Federation, project No. FEUZ-2020-0060. Additionally, M.I.O. was supported in part by the Ural Federal University project within the Priority-2030 Program, funded from the Ministry of Science and Higher Education of the Russian Federation. This work was also supported by the project “Swift heavy ions in research of iron-bearing nanomaterials”, No. of theme 04-5-1131-2017/2021, solved in cooperation with the Czech Republic and the JINR (3 + 3 projects), and also by internal IGA grant of Palacký University (IGA_PrF_2022_003). The authors from Palacký University Olomouc want to thank the facilitators of project CZ.02.1.01/0.0/0.0/17_049/0008408 of the Ministry of Education, Youth & Sports of the Czech Republic for their support as well.Acknowledgments: We are grateful to Z. Klencsár (Centre for Energy Research, Budapest), M. Miglierini (Technical University, Bratislava), I. Dézsi (Wigner Research Centre for Physics, Budapest), S. Kubuki, and K. Nomura (Tokyo Metropolitan University, Tokyo) for their participation in discussions, and L. Krupa (Czech Technical University in Prague, Czech Republic and Joint Institute for Nuclear Research, Dubna) for his help with the organization of project cooperation. The support by grants from the Hungarian National Research, Development and Innovation Office and by the Czech-Hungarian Intergovernmental Fund, Grant No. CZ-11/2007 (MEB040806) are acknowledged. M.I.O. is grateful for support from the Ministry of Science and Higher Education of the Russian Federation and from the Ural Federal University project within the Priority-2030 Program. This work was also carried out within the Agreement of Cooperation between the Ural Federal University (Ekaterinburg) and the Eötvös Loránd University (Budapest) and within the Memorandum of Understanding between the Ural Federal University (Ekaterinburg) and the Palacký University (Olomouc). Authors acknowledge the support of the project “Swift heavy ions in research of iron-bearing nanomaterials”, No. of theme 04-5-1131-2017/2021, solved in cooperation with the Czech Republic and the JINR (3 + 3 projects). Authors from Palacký University Olomouc appreciate the internal IGA grant of Palacký University (IGA_PrF_2022_013) and thank the facilitators of the project CZ.02.1.01/0.0/0.0/17_049/0008408 of the Ministry of Education, Youth & Sports of the Czech Republic as well

Study of neutron-rich isotopes near N=152 shell closure using Timepix type detectors integrated into the mass separator MASHA

The MASHA facility [1–3] was developed as a high precision mass-spectrometer for heavy and super heavy elements with masses up to 450 a.m.u. It uses ISOL (Isotope Separation On-Line) method. Its unique properties opens great prospective for the investigation of neutron-rich nuclei produced in multinucleon transfer reactions. Mainly nuclei near the neutron N = 126 and N = 152 shell closures are of great interest. This region of nuclei is not so far thoroughly enough investigated while its research has direct relation to the synthesis of super heavy elements. As is known the island of stability close to super heavy elements (Z = 112–118) exists due to the shell effects in nuclei. More detailed investigation of these shell effects can greatly help in the synthesis of next super heavy elements. Heavy neutron rich radon isotopes were produced in the multinucleon transfer reaction 40Ar + 232Th at Flerov Laboratory of Nuclear Reactions, Dubna. Radon isotopes with given masses were detected using two types of detectors: a multi-strip well-type detector (made in Canberra) and a position-sensitive quantum counting hybrid pixel detector of the Timepix type [4]. The latter detector has an array of 256x256 square pixels each with a pitch size of 55 um for the full sensitive area 14x14mm2. Radon isotopes implanted into the detector emit then alpha and beta particles until they reach the stable or long-lived isotopes at the end of their decay chains. The positions of radon isotopes, the tracks, times and energies of the beta particles were measured and analyzed. New software for the particle recognition and data analysis of the results obtained from the experiment was developed and used. It has been proven that MASHA + Timepix setup is a powerful instrument for investigation of neutron-rich isotopes far from stability limits