Mössbauer spectroscopic analysis of (Nd,Pr,Dy)2(Fe,Co,Ga)14B/α-Fe permanent magnetic nanocomposites

Mössbauer spectroscopic analysis of (Nd,Pr,Dy)2(Fe,Co,Ga)14B/α-Fe permanent magnetic nanocomposites

Božidar CEKIĆ, Valentin IVANOVSKI, Mirela Maria CODESCU, Ana UMIĆEVIĆ, Katarina ĆIRIĆ, Eugen MANTA

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Abstract. In this paper, it is reported the structural and magnetic properties of Nd13.7Pr0.7Dy0.2Fe73.1Co6.3Ga0.4B5.6 and Nd7.7Pr0.7Dy0.2Fe79.1Co6.3Ga0.4B5.6 magnetic nanocomposites, synthesized by melt-spinning and annealing methods. The Nd-Fe-B ribbons are melt-spun at v=30 m/s in high vacuum and annealed at 715oC for 4 min. in argon. Furthermore, X-ray diffraction and transmission 57Fe Mössbauer spectra at RT are used to investigate the effects of substituent elements: Dy, Pr, Co, Ga on the hard magnetic properties and microstructure of both nanocomposites. Analysis of Mössbauer spectra for Nd13.7Pr0.7Dy0.2Fe73.1Co6.3Ga0.4B5.6 is done in terms of ten Zeeman sextets, one paramagnetic doublet related to Nd1.1Fe4B4 phase and two hyperfine magnetic fields distributions extracted from spectrum. Similar result of analysis of the second nanocomposite is obtained with eleven sextets, one doublet and one distribution. One sextet corresponds to α-Fe phase, while we have identified six iron sextets corresponding to the six distinct iron sites in the Nd2Fe14B structure: 16k1, 16k2, 8j1, 8j2, 4c and 4e. The three remaining sextets belong to Fe3B structure with three inequivalent Fe sites: FeI(8g), FeII(8g) and FeIII(8g). The eleventh sextet of Nd7.7Pr0.7Dy0.2Fe79.1Co6.3Ga0.4B5.6 belongs to FeB. All relevant parameters for both nanocomposites: magnetic hyperfine field, isomer shift and quadrupole splitting are determined for each of these sites. To highlight the thermally induced structural transformations, the quenched samples have been analysed by differential scanning calorimetry and thermo-magnetic measurements. The magnetic properties, measured at RT on the quenched and annealed ribbons, revealed the relationship between the alloy chemical composition and processing.

NdFeB nanocomposites, XRD analysis, Mössbauer spectroscopy, Internal magnetic field, Quadrupole splitting

Published online 11/5/2018, 10 pages
Copyright © 2018 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: Božidar CEKIĆ, Valentin IVANOVSKI, Mirela Maria CODESCU, Ana UMIĆEVIĆ, Katarina ĆIRIĆ, Eugen MANTA, ‘Mössbauer spectroscopic analysis of (Nd,Pr,Dy)2(Fe,Co,Ga)14B/α-Fe permanent magnetic nanocomposites’, Materials Research Proceedings, Vol. 8, pp 70-79, 2018

DOI: http://dx.doi.org/10.21741/9781945291999-8

The article was published as article 8 of the book Powder Metallurgy and Advanced Materials

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

[1] K. J. Strnat, G. Hoffer, J. Oson, W. Ostertag, A family of new cobalt‐base permanent magnet materials, J. Appl. Phys. 38 (1967) 1001-1002. https://doi.org/10.1063/1.1709459
[2] M. Sagawa, S. Fujimura, N. Togawa, H. Yamamoto, Y. Matsuura, New material for permanent magnets on a base of Nd and Fe, J. Appl. Phys. 55 (1984) 2083-2087. https://doi.org/10.1063/1.333572
[3] J.J. Croat, J.F. Herbst, R.W. Lee, F.E. Pinkerton, Pr‐Fe and Nd‐Fe‐based materials: A new class of high‐performance permanent magnets, J. Appl. Phys. 55 (1984) 2078–2080. https://doi.org/10.1063/1.333571
[4] F.E. Pinkerton, W.R. Dunham, Mössbauer effect in R2Fe14B compounds, J. Appl. Phys. 57 (1985) 4121-4123. https://doi.org/10.1063/1.334638
[5] W. Kappel, M.M. Codescu, D. Popa, Losses in sintered NdFeB magnets, Rom. Rep. Phys. 56 (2004) 391–398.
[6] W. Kappel, M.M.Codescu, N. Stancu, D. Popa, Evaluation of the corrosion behavior of the permanent magnets based on rare earths, used in aeronautical industry, J. Optoelectron. Adv. Mat. 8 (2006) 523–526.
[7] M.M. Codescu, W. Kappel, D. Popa, Corrosion tests on alloys and permanent magnets based on NdFeB, used in aerospace industry, J. Optoelectron. Adv. Mat. 10 (2008) 790-793.
[8] H.A. Davies, A. Manaf, P.Z. Zhang, Nanocrystallinity and magnetic property enhancement in melt-spun iron-rare earth-base hard magnetic alloys, J. Mater. Eng. Perform. 2 (1993) 579-587. https://doi.org/10.1007/BF02661744
[9] G.C. Hadjipanayis, Nanophase hard magnets, J. Magn. Magn. Mater. 200 (1999) 373-391. https://doi.org/10.1016/S0304-8853(99)00430-8
[10] J.F. Herbst, R2Fe14B materials: Intrinsic properties and technological aspects, Rev. Mod. Phys. 63 (1991) 819-898. https://doi.org/10.1103/RevModPhys.63.819
[11] I.R. Betancourt, H.A. Davies, Magnetic properties of nanocrystalline didymium (Nd-Pr)-Fe-B alloys, J. Appl. Phys. 85 (1999) 5911-5913. https://doi.org/10.1063/1.369911
[12] Z.C. Wang, M.C. Zhang, F.B. Li, S.Z. Zhou, R. Wang, W. Gong, High-coercivity (NdDy)2(FeNb)14B–α–Fe nanocrystalline alloys, J. Appl. Phys. 81 (1997) 5097-5099. https://doi.org/10.1063/1.365187
[13] J.M. Yao, T.S. Chin, Coercivity of Ti‐modified (α‐Fe)‐Nd2Fe14B nanocrystalline alloys, J. Appl. Phys. 76 (1994) 7071-7073. https://doi.org/10.1063/1.358030
[14] A. Inoue, A. Kojima, A. Takeuchi, T. Masumoto, A. Makino, Hard and soft magnetic properties of nanocrystalline Fe–Nd–Zr–B alloys containing intergranular amorphous phase, J. Appl. Phys. 79 (1996) 4836-4836. https://doi.org/10.1063/1.361624
[15] I. Panagiatopoulos, L. Withanawasam, A. S. Murthy, G.S. Hadjipanayis, E.W. Singleton, D.J. Sellmyer, Magnetic hardening of melt‐spun nanocomposite Nd2Fe14B/Fe magnets, J. Appl. Phys. 79 (1996) 4827-4829. https://doi.org/10.1063/1.361621
[16] T. Schrefl, J. Fidler, Födermayr, Modelling of exchange-spring permanent magnets, J. Magn. Magn. Mater. 177-181 (1998) 970-975. https://doi.org/10.1016/S0304-8853(97)00653-7
[17] R.A. Brand, (2008) WinNormos Mössbauer fitting program, Universität Duisburg.
[18] C. You, X.K. Sun, W. Liu, B. Cui, X. Zhao, D. Geng, Z. Zhang, Effects of W and Co additions on the phase transformation and magnetic properties of nanocomposite Nd2Fe14B/α-Fe magnets, J. Phys. D: Appl. Phys. 35 (2002) 943-950. https://doi.org/10.1088/0022-3727/35/10/301
[19] B. Cekič, V. Ivanovski, M.M. Codescu, A. Umicevic, T. Barudzija, E.A. Patroi, Mössbauer Spectroscopic Analysis of Nd2Fe14B/α-Fe Hard Magnetic Nanocomposites, Sol. St. Phen. 170 (2011) 154-159. https://doi.org/10.4028/www.scientific.net/SSP.170.154
[20] R. Kamal, Y. Andersson, Mössbauer spectroscopic studies of Nd2Fe14B, Phys. Rev. B 32 (1985) 1756-1760. https://doi.org/10.1103/PhysRevB.32.1756
[21] W. Kappel, M.M. Codescu, Nd2Fe14B/α-Fe Hard Magnetic Nanocomposite. Performances and Limits, Rom. J. Phys. 49 (2004) 733-741.
[22] W. Kappel, M.M. Codescu, M. Valeanu, N. Stancu, J. Pintea, F. Lifei, A. Jianu, D. Patroi, E. Patroi, Influence of the recrystallization processes on the structure and magnetic properties of the Nd2Fe14B/alpha-Fe nanocomposites, J. Optoelectron. Adv. Mat. 9 (2007) 1825-1828.