Magnetocrystalline anisotropy of small CoPt binary alloy metal clusters: interplay between structure, chemical composition, and spin-orbit coupling
Source abstract
Abstract
The ground-state magnetic properties of ConPtm binary alloy clusters of size N = n + m ≤ 9 are studied systematically as a function of size, composition, and chemical order in the framework of the generalized gradient approximation (GGA) to density functional theory (DFT). Interestingly, strong cluster-size and chemical-composition dependence exhibiting substantial values (0.4–22 meV/atom) in the magnetic anisotropy energy (MAE) are revealed. Such behavior crucially depends on the Pt moments induced by the proximity to Co, and on the resulting spin-orbit interactions at the Pt atoms. Moreover, we show that the MAEs and direction of magnetization can be tuned to some extent by varying the Pt concentration showing spin reorientations and the easy axis of magnetization is cluster size dependent. A thorough cluster-geometry optimizations together with a collinear and noncollinear magnetic moment arrangement sampling including the spin-orbit coupling are carried out to identify the ground-state and the low-lying structures. The relative directions between Co and Pt magnetic moments induced by spin-orbit interaction show an early tendency to arrange the magnetic moments along with Co and Pt layers in a way resembling the L10 phase with tetragonal crystal lattice which can be appreciated in the clusters having N ≥ 5 atoms. Our results show that planar-like structures are preferred in small cluster sizes (N ≤ 4 atoms) while for N ≥ 5 tend to form three-dimensional core-shell compact structures with a composition around 50/50% ordering maximizing the number of Co-Pt bonds. The average magnetic moment per atom $\bar {\mu }T$ increases approximately linearly with Co content and important enhancement of the local Co moments is observed as a result of Pt doping for n + m ≤ 4. This is mainly a consequence of the increase in the number of Co d holes due to Co to Pt charge transfer. Finally, our results show important spin and orbital moments induced at the Pt atoms as well as significant orbital moments at the Co atoms .
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Magnetic properties of thin films · Magnetic and transport properties of perovskites and related materials · Heusler alloys: electronic and magnetic properties
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (61)
Show source-provided references
1. Airola MB, Morse MD (2002) Rotationally resolved spectroscopy of Pt2. J Chem Phys 116(4):1313–1317. Retrieved from https://doi.org/10.1063/1.142875310.1063/1.1428753 ↗
2. Anton J, Jacob T, Fricke B, Engel E (2002) Relativistic density functional calculations for Pt2. Phys Rev Lett 89:213001. Retrieved from https://link.aps.org/doi/10.1103/PhysRevLett.89.213001https://doi.org/10.1103/PhysRevLett.89.21300110.1103/PhysRevLett.89.213001 ↗
3. Bansmann J, Baker S, Binns C, Blackman J, Buecher J-P, Dorantes-D’avila J, Dupuis V, Favre L, Kechrakos D, Kleibert A, Meiwes-Broer K-H, Pastor G M, Perez A, Toulemonde O, Trohidou KN, Tuaillon J, Xie Y (2005). Magnetic and structural properties of isolated and assembled clusters. Surface Science Reports, 56(6),. Retrieved from http://www.sciencedirect.com/science/article/pii/S0167572904001128https://doi.org/10.1016/S0167-5729(04)00112-810.1016/S0167-5729(04)00112-8 ↗
4. Barcaro G, Ferrando R, Fortunelli A, Rossi G (2010) Exotic supported CoPt nanostructures: From clusters to wires. J Phys Chem Lett 1(1):111–115. Retrieved from https://doi.org/10.1021/jz900076m10.1021/jz900076m ↗
5. Barden C J, Rienstra-Kiracofe JC, Schaefer HF (2000) Homonuclear 3d transition-metal diatomics: A systematic density functional theory study. J Chem Phys 113(2):690–700. Retrieved from https://doi.org/10.1063/1.48191610.1063/1.481916 ↗
6. Blöchl PE (1994) Projector augmented-wave method. Phys Rev B 50:17953–17979. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.50.17953https://doi.org/10.1103/PhysRevB.50.1795310.1103/PhysRevB.50.17953 ↗
7. Błoński P, Dennler S, Hafner J (2011) Strong spin–orbit effects in small pt clusters: Geometric structure, magnetic isomers and anisotropy. J Chem Phys 134(3):034107. Retrieved from https://doi.org/10.1063/1.353079910.1063/1.3530799 ↗
8. Castro M, Jamorski C, Salahub DR (1997) Structure, bonding, and magnetism of small Fen, Fon, and Nin clusters, n ≤ 5. Chem Phys Lett 271(1):133–142. Retrieved from http://www.sciencedirect.com/science/article/pii/S000926149700420Xhttps://doi.org/10.1016/S0009-2614(97)00420-X10.1016/S0009-2614(97)00420-X ↗
9. Dannenberg A, Gruner M E, Hucht A, Entel P (2009) Surface energies of stoichiometric FePt and CoPt alloys and their implications for nanoparticle morphologies. Phys Rev B 80:245438. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.80.245438https://doi.org/10.1103/PhysRevB.80.24543810.1103/PhysRevB.80.245438 ↗
10. Dupuis V, Favre L, Stanescu S, Tuaillon-Combes J, Bernstein E, Perez A (2004) Magnetic assembled nanostructures from pure and mixed Co-based clusters. J Phys Condensed Matter 16(22):S2231–S2240. Retrieved from https://doi.org/10.1088/0953-8984/16/22/02410.1088/0953-8984/16/22/024 ↗
11. Entel P, Gruner ME (2009) Large-scale ab initio simulations of binary transition metal clusters for storage media materials. J Phys Condensed Matter 21(6):064228. Retrieved from https://doi.org/10.1088/0953-8984/21/6/06422810.1088/0953-8984/21/6/064228 ↗
12. Fan H-J, Liu C-W, Liao M-S (1997) Geometry, electronic structure and magnetism of small Con (n = 2-8) clusters. Chem Phys Lett 273(5):353–359. Retrieved from http://www.sciencedirect.com/science/article/pii/S0009261497005344https://doi.org/10.1016/S0009-2614(97)00534-410.1016/S0009-2614(97)00534-4 ↗
13. Favre L, Dupuis V, Bernstein E, Mélinon P, Péerez A, Stanescu S, Hodeau J-L (2006) Structural and magnetic properties of CoPt mixed clusters. Phys Rev B 74:14439. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.74.014439https://doi.org/10.1103/PhysRevB.74.01443910.1103/PhysRevB.74.014439 ↗
14. Feng R-J, Xu X-H, Wu H-S (2007) Electronic structure and magnetism in (CoPt)n (n ≤ 5) clusters. J Magn Magn Mater 308(1):131–136. Retrieved from http://www.sciencedirect.com/science/article/pii/S030488530600864Xhttps://doi.org/10.1016/j.jmmm.2006.05.01210.1016/j.jmmm.2006.05.012 ↗
15. Gambardella P, Rusponi S, Veronese M, Dhesi SS, Grazioli C, Dallmeyer A, Brune H (2003) Giant magnetic anisotropy of single cobalt atoms and nanoparticles. Science 300 (5622):1130–1133. Retrieved from https://science.sciencemag.org/content/300/5622/1130https://doi.org/10.1126/science.108285710.1126/science.1082857 ↗
16. Gradmann U (1993) Chapter 1 magnetism in ultrathin transition metal films. In: (vol 7, pp 1–96). Elsevier. Retrieved from http://www.sciencedirect.com/science/article/pii/S1567271905800423https://doi.org/10.1016/S1567-2719(05)80042-310.1016/S1567-2719(05)80042-3 ↗
17. Gruner M E, Entel P (2009) Simulating functional magnetic materials on supercomputers. Journal of Physics: Condensed Matter 21(29):293201. Retrieved from https://doi.org/10.1088/0953-8984/21/29/29320110.1088/0953-8984/21/29/293201 ↗
18. Gruner ME, Rollmann G, Entel P, Farle M (2008) Multiply twinned morphologies of FePt and CoPt nanoparticles. Phys Rev Lett 100:087203. Retrieved from https://link.aps.org/doi/10.1103/PhysRevLett.100.087203https://doi.org/10.1103/PhysRevLett.100.08720310.1103/PhysRevLett.100.087203 ↗
19. Hales D A, Su C, Lian L, Armentrout P B (1994) Collision-induced dissociation of Co+n (n = 2–8) with Xe: Bond energies of cationic and neutral cobalt clusters, dissociation pathways, and structures. J Chem Phy 100(2):1049–1057. Retrieved from https://doi.org/10.1063/1.46663610.1063/1.466636 ↗
20. Hellwig O, Berger A, Thomson T, Dobisz E, Bandic ZZ, Yang H, Fullerton EE (2007) Separating dipolar broadening from the intrinsic switching field distribution in perpendicular patterned media. Appl Phys Lett 90(16):162516. Retrieved from https://doi.org/10.1063/1.273074410.1063/1.2730744 ↗
21. Henkelman G, Arnaldsson A, Jónsson H (2006) A fast and robust algorithm for bader decomposition of charge density. Comput Mater Sci 36(3):354–360. https://doi.org/10.1016/j.commatsci.2005.04.01010.1016/j.commatsci.2005.04.010 ↗
22. Hohenberg P, Kohn W (1964) Inhomogeneous electron gas. Phys Rev 136:B864–B871. Retrieved from https://link.aps.org/doi/10.1103/PhysRev.136.B864https://doi.org/10.1103/PhysRev.136.B86410.1103/PhysRev.136.B864 ↗
23. Jamet M, Négrier M, Dupuis V, Tuaillon-Combes J, Mélinon P, Pérez A, Baguenard B (2001) Interface magnetic anisotropy in cobalt clusters embedded in a platinum matrix. J Magn Magn Mater 237(3):293–301. Retrieved from http://www.sciencedirect.com/science/article/pii/S0304885301006953https://doi.org/10.1016/S0304-8853(01)00695-310.1016/S0304-8853(01)00695-3 ↗
24. Knickelbein MB (2007) Magnetic moments of small bimetallic clusters: ConMnm. Phys Rev B 75:014401. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.75.014401https://doi.org/10.1103/PhysRevB.75.01440110.1103/PhysRevB.75.014401 ↗
25. Kohn W, Sham LJ (1965) Retrieved from https://link.aps.org/doi/10.1103/PhysRev.140.A1133https://doi.org/10.1103/PhysRev.140.A1133. Phys Rev 140:A1133–A113810.1103/PhysRev.140.A1133 ↗
26. Kresse G, Furthmüller J (1996) Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys Rev B 54:11169–11186. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.54.11169https://doi.org/10.1103/PhysRevB.54.1116910.1103/PhysRevB.54.11169 ↗
27. Kresse G, Hafner J (1993) Ab initio molecular dynamics for liquid metals. Phys Rev B 47:558–561. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.47.558https://doi.org/10.1103/PhysRevB.47.55810.1103/PhysRevB.47.558 ↗
28. Kresse G, Joubert D (1999) From ultrasoft pseudopotentials to the projector augmented-wave method. Phys Rev B 59:1758–1775. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.59.1758https://doi.org/10.1103/PhysRevB.59.175810.1103/PhysRevB.59.1758 ↗
29. Kumar V, Kawazoe Y (2008) Evolution of atomic and electronic structure of Pt clusters: Planar, layered, pyramidal, cage, cubic, and octahedral growth. Phys Rev B 77:205418. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.77.205418https://doi.org/10.1103/PhysRevB.77.20541810.1103/PhysRevB.77.205418 ↗
30. Kumbhar A, Spinu L, Agnoli F, Wang K, Zhou W, O’Connor CJ (2001) Magnetic properties of cobalt and cobalt-platinum alloy nanoparticles synthesized via microemulsion technique. IEEE Trans Magn 37(4):2216–2218. https://doi.org/10.1109/20.95112810.1109/20.951128 ↗
31. Liou SH, Huang S, Klimek E, Kirby RD, Yao YD (1999) Enhancement of coercivity in nanometer-size CoPt crystallites. J Appl Phys 85(8):4334–4336. Retrieved from https://doi.org/10.1063/1.37035910.1063/1.370359 ↗
32. Maret M, Cadeville M, Poinsot R, Herr A, Beaurepaire E, Monier C (1997) Structural order related to the magnetic anisotropy in epitaxial (111) CoPt3 alloy films. J Magn Magn Mater 166(1):45–52. Retrieved from http://www.sciencedirect.com/science/article/pii/S0304885396004532https://doi.org/10.1016/S0304-8853(96)00453-210.1016/S0304-8853(96)00453-2 ↗
33. Maret M, Cadeville M, Staiger W, Beaurepaire E, Poinsot R, Herr A (1996) Retrieved from http://www.sciencedirect.com/science/article/pii/0040609095070494https://doi.org/10.1016/0040-6090(95)07049-4. Thin Solid Films 275(1):224–22710.1016/0040-6090(95)07049-4 ↗
34. Mermin ND (1965) Thermal properties of the inhomogeneous electron gas. Phys Rev 137:A1441–A1443. Retrieved from https://link.aps.org/doi/0.1103/PhysRev.137.A1441https://doi.org/10.1103/PhysRev.137.A144110.1103/PhysRev.137.A1441 ↗
35. Plumer ML, van Ek DWJ (2001) The physics of ultra-high-density magnetic recording (Vol. 41). Springer-Verlag , Berlin. https://doi.org/10.1007/978-3-642-56657-810.1007/978-3-642-56657-8 ↗
36. Moskovkin P, Pisov S, Hou M, Raufast C, Tournus F, Favre L, Dupuis V (2007) Model predictions and experimental characterization of Co-Pt alloy clusters. Eur Phys J D 43:27–32. Retrieved from https://doi.org/10.1140/epjd/e2007-00066-010.1140/epjd/e2007-00066-0 ↗
37. Muñoz-Navia M, Dorantes-D’avila J, Zitoun D, Amiens C, Jaouen N, Rogalev A, Pastor GM (2009) Tailoring the magnetic anisotropy in CoRh nanoalloys. Appl Phys Lett 95(23):233107. Retrieved from https://doi.org/10.1063/1.327200010.1063/1.3272000 ↗
38. Mlynarski P, Iglesias M, Pereiro M, Baldomir D, Wojtczak L (1999) Properties and structure of small cobalt clusters: Nonlocal density functional calculations. Vacuum 54 (1):143–149. Retrieved from http://www.sciencedirect.com/science/article/pii/S0042207X98004503https://doi.org/10.1016/S0042-207X(98)00450-310.1016/S0042-207X(98)00450-3 ↗
39. Penuelas J, Ouerghi A, Andreazza-Vignolle C, Gierak J, Bourhis E, Andreazza P, Sauvage T (2009) Local tuning of CoPt nanoparticle size and density with a focused ion beam nanowriter. Nanotechnology 20(42):425304. Retrieved from https://doi.org/10.1088/0957-4484/20/42/42530410.1088/0957-4484/20/42/425304 ↗
40. Perdew JP, Burke K, Wang Y (1996) Generalized gradient approximation for the exchange-correlation hole of a many-electron system. Phys Rev B 54:16533–16539. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.54.16533https://doi.org/10.1103/PhysRevB.54.1653310.1103/PhysRevB.54.16533 ↗
41. Perdew J P, Chevary JA, Vosko SH, Jackson K A, Pederson M R, Singh D J, Fiolhais C (1992) Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. Phys Rev B 46:6671–6687. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.46.6671https://doi.org/10.1103/PhysRevB.46.667110.1103/PhysRevB.46.6671 ↗
42. Pereiro M, Man’kovsky S, Baldomir D, Iglesias M, Mlynarski P, Valladares M, Arias JE (2001) Model potential nonlocal density functional calculations of small cobalt clusters, Con ≤ 5. Comput Mater Sci 22(1):118–122. Retrieved from http://www.sciencedirect.com/science/article/pii/S092702560100177Xhttps://doi.org/10.1016/S0927-0256(01)00177-X10.1016/S0927-0256(01)00177-X ↗
43. Rollmann G, Sahoo S, Hucht A, Entel P (2008) Magnetism and chemical ordering in binary transition metal clusters. Phys Rev B 78:134404. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.78.134404https://doi.org/10.1103/PhysRevB.78.13440410.1103/PhysRevB.78.134404 ↗
44. Ruiz-Díaz P, Mun̂oz-Navia M, Dorantes-D’avila J, Ruiz-Dí P (2018) Charge-doping and chemical composition-driven magnetocrystalline anisotropy in CoPt core-shell alloy clusters. J Nanopart Res 20:58. Retrieved from https://link.springer.com/article/10.1007/s11051-018-4164-zhttps://doi.org/10.1007/s11051-018-4164-z10.1007/s11051-018-4164-z ↗
45. Sahoo S, Hucht A, Gruner ME, Rollmann G, Entel P, Postnikov A, Sil S (2010) Magnetic properties of small pt-capped fe, co, and ni clusters: A density functional theory study. Phys Rev B 2:054418. Retrieved from https://link.aps.org/doi/10.1103/PhysRevB.82.054418https://doi.org/10.1103/PhysRevB.82.05441810.1103/PhysRevB.82.054418 ↗
46. Sanville E, Kenny SD, Smith R (2007) Improved grid-based algorithm for bader charge allocation. J Computa Chem 28(5):899–908. Retrieved from https://onlinelibrary.wiley.com/doi/abs/10.1002/jcc.20575https://doi.org/10.1002/jcc.2057510.1002/jcc.20575 ↗
47. Shaw J M, Rippard W H, Russek S E, Reith T, Falco CM (2007) Origins of switching field distributions in perpendicular magnetic nanodot arrays. J Appl Phys 101(2):023909. Retrieved from https://doi.org/10.1063/1.243139910.1063/1.2431399 ↗
48. Sun S, Murray CB, Weller D, Folks L, Moser A (2000) Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices. Science 287(5460):1989–1992. Retrieved from https://science.sciencemag.org/content/287/5460/1989https://doi.org/10.1126/science.287.5460.198910.1126/science.287.5460.1989 ↗
49. Tamion A, Hillenkamp M, Tournus F, Bonet E, Dupuis V (2009) Accurate determination of the magnetic anisotropy in cluster-assembled nanostructures. Appl Phys Lett 95(6):062503. Retrieved from https://doi.org/10.1063/1.320095010.1063/1.3200950 ↗
50. Tang W, Sanville E, Henkelman G (2009) Retrieved from https://doi.org/10.1088/0953-8984/21/8/084204. Journal of Physics: Condensed Matter 21(8):08420410.1088/0953-8984/21/8/084204 ↗
51. Thomson T, Hu G, Terris BD (2006) Intrinsic distribution of magnetic anisotropy in thin films probed by patterned nanostructures. Phys Rev Lett 96:257204. Retrieved from https://link.aps.org/doi/10.1103/PhysRevLett.96.257204https://doi.org/10.1103/PhysRevLett.96.25720410.1103/PhysRevLett.96.257204 ↗
52. Valvidares SM, Dorantes-Dávila J, Isern H, Ferrer S, Pastor GM (2010) Interface-driven manipulation of the magnetic anisotropy of ultrathin co films on Pt(111): Substrate deposition of hydrogen and model calculations. Phys Rev B 81:024415. Retrieved from https://doi.org/10.1103/PhysRevB.81.02441510.1103/PhysRevB.81.024415 ↗
53. Vaz CAF, Bland JAC, Lauhoff G (2008) Magnetism in ultrathin film structures. Reports Progr Phys 71(5):056501. Retrieved from https://doi.org/10.1088/0034-4885/71/5/05650110.1088/0034-4885/71/5/056501 ↗
54. Vita AD, Gillan MJ (1992) The energetics of hydrogen in aluminium calculated from first principles. Journal of Physics: Condensed Matter 4(2):599–611. Retrieved from https://doi.org/10.1088/0953-8984/4/2/02810.1088/0953-8984/4/2/028 ↗
55. Xiao L, Wang L (2004) Structures of Platinum clusters: Planar or spherical. J Phys Chem A 108(41):8605–8614. Retrieved from https://doi.org/10.1021/jp048503510.1021/jp0485035 ↗
56. Yanagisawa M, Shiota N, Yamaguchi H, Suganuma Y (1983) Corrosion-resisting co-pt thin film medium for high density recording. IEEE Trans Magn 19(5):1638–1640. https://doi.org/10.1109/TMAG.1983.106273810.1109/TMAG.1983.1062738 ↗
57. Yang S H, Drabold D A, Adams JB, Ordejón P, Glassford K (1997) Density functional studies of small platinum clusters. Journal of Physics: Condensed Matter 9(5):L39–L45. Retrieved from https://doi.org/10.1088/0953-8984/9/5/00210.1088/0953-8984/9/5/002 ↗
58. Yin S, Moro R, Xu X, de Heer WA (2007) Magnetic enhancement in cobalt-manganese alloy clusters. Phys Rev Lett 98:113401. Retrieved from https://link.aps.org/doi/10.1103/PhysRevLett.98.113401https://link.aps.org/doi/10.1103/PhysRevLett.98.113401https://doi.org/10.1103/PhysRevLett.98.113401https://doi.org/10.1103/PhysRevLett.98.11340110.1103/PhysRevLett.98.113401 10.1103/PhysRevLett.98.113401 ↗
59. Yu M, Liu Y, Sellmyer DJ (2000) Nanostructure and magnetic properties of composite CoPt:c films for extremely high-density recording. J Appl Phys 87(9):6959–6961. Retrieved from https://doi.org/10.1063/1.37289910.1063/1.372899 ↗
60. Zarechnaya E, Skorodumova N, Simak S, Johansson B, Isaev E (2008) Theoretical study of linear monoatomic nanowires, dimer and bulk of Cu, Ag, Au, Ni, Pd and Pt. Comput Mater Sci 43(3):522–530. Retrieved from http://www.sciencedirect.com/science/article/pii/S0927025608000037https://doi.org/10.1016/j.commatsci.2007.12.01810.1016/j.commatsci.2007.12.018 ↗
61. Zitoun D, Respaud M, Fromen M-C, Casanove MJ, Lecante P, Amiens C, Chaudret B (2002) Magnetic enhancement in nanoscale corh particles. Phys Rev Lett 89:n. Retrieved from https://link.aps.org/doi/10.1103/PhysRevLett.89.037203https://doi.org/10.1103/PhysRevLett.89.03720310.1103/PhysRevLett.89.037203 ↗