Physical and chemical properties of Co nm Cu m nanoclusters with n = 2–6 atoms via ab-initio calculations

  • Marcos Pérez
  • Francisco Muñoz
  • José Mejía-López
  • Gerardo Martínez
Research Paper


We present ab-initio density-functional calculations of the structural, magnetic, and chemical properties of cobalt–copper clusters (1 nm in size) with two to six atoms. We applied several search methods to find the most stable configurations for all stoichiometries. Particular attention is given to the relation between the geometric and magnetic structures. The clusters behavior is basically governed by the Co–Co interaction and to a lesser extent by the Co–Cu and Cu–Cu interactions. A tendency for Co-clumping is observed. Such information is quite relevant for segregation processes found in bulk Co–Cu alloys. For a given cluster size, magnetic moments increase mostly by 2μB per Co-substitution coming from the cobalt d-states, while for some cases s-electrons give rise to itinerant magnetism. Magnetic moment results are also consistent with the ultimate jellium model because of a 2D to 3D geometrical transition. The chemical potential indicates less chemical stability with the Co atoms, while the molecular hardness can be linked mostly to the ionization potential for these small clusters.


Cobalt–copper ferromagnetic nanoclusters Phase separation and segregation Magnetic properties of nanostructures Electronic structure of nanoscale materials Modeling and simulation 



Support for this study from CNPq (Brasil) and CONICYT (Chile), Joint Project CIAM 490891/2008-0 is gratefully acknowledged. We also thank the Millennium Science Nucleus (Chile), Project P10-061-F; Doctorate Program PUC (Chile), Project 06/2009; FONDECYT (Chile), Project 1100365; and CAPES/PROCAD (Brasil) Project 059/2007. Computer time from the National Supercomputing Center CENAPAD CESUP/UFRGS is also acknowledged.


  1. Bagno P, Jepsen O, Gunnarsson O (1989) Ground-state properties of third-row elements with nonlocal density functionals. Phys Rev B 40:1997–2000CrossRefGoogle Scholar
  2. Baibich MN, Broto JM, Fert A, Nguyenvan Dau F, Petroff F, Etienne P, Creuzet G, Friederich A, Chazelas J (1988) Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. Phys Rev Lett 61:2472–2475CrossRefGoogle Scholar
  3. Bakonyi I, Simon E, Tóth BG, Péter L, Kiss LF (2009) Giant magnetoresistance in electrodeposited Co–Cu/Cu multilayers: origin of the absence of oscillatory behavior. Phys Rev B 79:174421CrossRefGoogle Scholar
  4. Becke AD (1988) Density-functional exchange-energy approximation with correct asymptotic behavior. Phys Rev A 38:3098–310CrossRefGoogle Scholar
  5. Berkowitz AE, Mitchell JR, Carey MJ, Young AP, Zhang S, Spada FE, Parker FT, Hutten A, Thomas G (1992) Giant magnetoresistance in heterogeneous Cu–Co alloys. Phys Rev Lett 68:3745–3748CrossRefGoogle Scholar
  6. Castro M, Jamorski C, Salahub DR (1997) Structure, bonding, and magnetism of small Fen, Con, and Nin clusters, n ≤ 5. Chem Phys Lett 271:133–142CrossRefGoogle Scholar
  7. Cezar JC, Tolentino HC, Knobel M (2003) Structural, magnetic, and transport properties of Co nanoparticles within a Cu matrix. Phys Rev B 68:054404CrossRefGoogle Scholar
  8. Chattaraj PK, Liu GH, Parr RG (1995) The maximum hardness principle in the Gyftopoulos–Hatsopoulos three-level model for an atomic or molecular species and its positive and negative ions. Chem Phys Lett 237:171–176CrossRefGoogle Scholar
  9. Datta S, Kabir M, Ganguly S, Sanyal B, Saha-Dasgupta T, Mookerjee A (2007) Structure, bonding, and magnetism of cobalt clusters from first-principles calculations. Phys Rev B 76:014429CrossRefGoogle Scholar
  10. Dong CD, Gong XG (2008) Magnetism enhanced layer-like structure of small cobalt clusters. Phys Rev B 78:020409CrossRefGoogle Scholar
  11. Fan HJ, Liu CW, Liao MS (1997) Geometry, electronic structure and magnetism of small Con (n = 2–8) clusters. Chem Phys Lett 273:353–359CrossRefGoogle Scholar
  12. Fan X, Mashimo T, Huang X, Kagayama T, Chiba A, Koyama K, Motokawa M (2004) Magnetic properties of Co–Cu metastable solid solution alloys. Phys Rev B 69:094432CrossRefGoogle Scholar
  13. Ferrando R, Jellinek J, Johnston RL (2008) Nanoalloys: from theory to applications of alloy clusters and nanoparticles. Chem Rev 108:845–910CrossRefGoogle Scholar
  14. Ganguly S, Kabir M, Datta S, Sanyal B, Mookerjee A (2008) Magnetism in small bimetallic Mn–Co clusters. Phys Rev B 78:014402CrossRefGoogle Scholar
  15. Ghanty TK, Banerjee A, Chakrabarti A (2010) Structures and the electronic properties of Au19X clusters (X = Li, Na, K, Rb, Cs, Cu, and Ag). J Phys Chem C 114:20–27CrossRefGoogle Scholar
  16. Ghosh SK, Grover AK, Chowdhury P, Gupta SK, Ravikumar G, Aswal DK, Senthil Kumar M, Dusane RO (2006) High magnetoresistance and low coercivity in electrodeposited Co/Cu granular multilayers. Appl Phys Lett 89:132507CrossRefGoogle Scholar
  17. Hales DA, Su CX, Lian L, Armentrout PB (1994) Collision-induced dissociation of Con+ (n = 2–18) with Xe: bond energies of cationic and neutral cobalt clusters, dissociation pathways, and structures. J Chem Phys 100:1049–1057CrossRefGoogle Scholar
  18. Hickey BJ, Howson MA, Musa SO, Wiser N (1995) Giant magnetoresistance for superparamagnetic particles: melt-spun granular CuCo. Phys Rev B 51:667–669CrossRefGoogle Scholar
  19. Jamorski C, Martínez A, Castro M, Salahub DR (1997) Structure and properties of cobalt clusters up to the tetramer: a density-functional study. Phys Rev B 55:10905–10921CrossRefGoogle Scholar
  20. Jaque P, Toro-Labbé A (2002) Characterization of copper clusters through the use of density functional theory reactivity descriptors. J Chem Phys 117:3208–3218CrossRefGoogle Scholar
  21. Jaque P, Toro-Labbé A (2004) The formation of neutral copper clusters from experimental binding energies and reactivity descriptors. J Phys Chem B 108:2568–2574CrossRefGoogle Scholar
  22. Ju SP, Lo YC, Sun SJ, Chang JG (2005) Investigation on the structural variation of CoCu nanoparticles during the annealing process. J Phys Chem B 109:20805–20809CrossRefGoogle Scholar
  23. Kabir M, Mookerjee A, Bhattacharya AK (2004a) Copper clusters: electronic effect dominates over geometric effect. Eur Phys J D 31:477–485CrossRefGoogle Scholar
  24. Kabir M, Mookerjee A, Bhattacharya AK (2004b) Structure and stability of copper clusters: a tight-binding molecular dynamics study. Phys Rev A 69:043203CrossRefGoogle Scholar
  25. Knorr N, Schneider MA, Diekhöner L, Wahl P, Kern K (2002) Kondo effect of single Co adatoms on Cu surfaces. Phys Rev Lett 88:096804CrossRefGoogle Scholar
  26. Kohn W, Becke AD, Parr RG (1996) Density functional theory of electronic structure. J Phys Chem 100:12974–12980CrossRefGoogle Scholar
  27. Kolehmainen J, Häkkinen H, Manninen M (1997) Metal clusters on an inert surface: a simple mode. Z Phys D 40:306–309CrossRefGoogle Scholar
  28. Koskinen M, Lipas PO, Manninen M (1995) Electron-gas clusters: the ultimate jellium model. Z Phys D 35:285–297CrossRefGoogle Scholar
  29. Kresse G, Furthmüller J (1996a) Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput Mat Sci 6:15–50CrossRefGoogle Scholar
  30. Kresse G, Furthmüller J (1996b) Efficient iterative schemes for ab-initio total-energy calculations using a plane-wave basis set. Phys Rev B 54:11169–11186CrossRefGoogle Scholar
  31. Kresse G, Hafner J (1993) Ab-initio molecular dynamics for liquid metals. Phys Rev B 47:558–561CrossRefGoogle Scholar
  32. Kresse G, Hafner J (1994) Norm-conserving and ultrasoft pseudopotentials for first-row and transition-elements. J Phys Condens Matter 6:8245–8257CrossRefGoogle Scholar
  33. Kresse G, Joubert D (1999) From ultrasoft pseudopotentials to the projector augmented-wave method. Phys Rev B 59:1758–1775CrossRefGoogle Scholar
  34. Kübbler J (1981) Magnetic moments of ferromagnetic and antiferromagnetic bcc and fcc iron. Phys Lett A 81:81–83CrossRefGoogle Scholar
  35. Kullie O, Zhang H, Kolb D (2008) Relativistic and non-relativistic local-density functional, benchmark results and investigation on the dimers Cu2, Ag2, Au2, Rg2. Chem Phys 351:106–110CrossRefGoogle Scholar
  36. Leopold DG, Lineberger WC (1986) A study of the low-lying electronic states of Fe2 and Co2 by negative ion photoelectron spectroscopy. J Chem Phys 85:51–55CrossRefGoogle Scholar
  37. Lu QL, Zhu LZ, Ma L, Wang GH (2005) Magnetic properties of Co/Cu and Co/Pt bimetallic clusters. Chem Phys Lett 407:176–179CrossRefGoogle Scholar
  38. Mejía-López J, García G, Romero AH (2009) Physical and chemical characterization of Pt12−nCun clusters via ab-initio calculations. J Chem Phys 131:044701CrossRefGoogle Scholar
  39. Miranda MGM, Estévez-Rams E, Martínez G, Baibich MN (2003) Phase separation in Cu90Co10 high-magnetoresistance materials. Phys Rev B 68:014434CrossRefGoogle Scholar
  40. Miranda MGM, da Rosa AT, Hinrichs R, Golla-Schindler U, Antunes AB, Martínez G, Estévez-Rams E, Baibich MN (2006) Spinodal decomposition and giant magnetoresistance. Phys B 384:175–178CrossRefGoogle Scholar
  41. Néel N, Kröger J, Berndt R, Wehling TO, Lichtenstein AI, Katsnelson MI (2008) Controlling the Kondo effect in CoCun clusters atom by atom. Phys Rev Lett 101:266803CrossRefGoogle Scholar
  42. Parkin SSP, More N, Roche KP (1990) Oscillations in exchange coupling and magnetoresistance in metallic superlattice structures: Co/Ru, Co/Cr, and Fe/Cr. Phys Rev Lett 64:2304–2307CrossRefGoogle Scholar
  43. Parr RG, Pearson RG (1983) Absolute hardness: companion parameter to absolute electronegativity. J Am Chem Soc 105:7512–7516CrossRefGoogle Scholar
  44. Parr RG, Yang M (1984) Density functional approach to the frontier-electron theory of chemical reactivity. J Am Chem Soc 106:4049–4050CrossRefGoogle Scholar
  45. Perdew JP (1986) Density-functional approximation for the correlation energy of the inhomogeneous electron gas. Phys Rev B 33:8822–8824CrossRefGoogle Scholar
  46. Perdew JP, Wang Y (1986) Accurate and simple density functional for the electronic exchange energy: generalized gradient approximation. Phys Rev B 33:8800–8802CrossRefGoogle Scholar
  47. Perdew JP, Wang Y (1992) Accurate and simple analytic representation of the electron-gas correlation energy. Phys Rev B 45:13244–13249CrossRefGoogle Scholar
  48. Perdew JP, Burke K, Ernzerhof M (1996a) Generalized gradient approximation made simple. Phys Rev Lett 77:3865–3868CrossRefGoogle Scholar
  49. Perdew JP, Burke K, Wang Y (1996b) Generalized gradient approximation for the exchange-correlation hole of a many-electron system. Phys Rev B 54:16533–16539CrossRefGoogle Scholar
  50. Quaas N, Wenderoth NM, Weismann A, Ulbrich RG, Schönhammer K (2004) Kondo resonance of single Co atoms embedded in Cu(111). Phys Rev B 69:201103CrossRefGoogle Scholar
  51. Rabedeau TA, Toney MF, Marks RF, Parkin SSP, Farrow RFC, Harp GR (1993) Giant magnetoresistance and Co-cluster structure in phase-separated Co–Cu granular alloys. Phys Rev B 48:16810–16813CrossRefGoogle Scholar
  52. Rastei MV, Heinrich B, Limot L, Ignatiev PA, Stepanyuk VS, Bruno P, Bucher JP (2007) Size-dependent surface states of strained cobalt nanoislands on Cu(111). Phys Rev Lett 99:246102CrossRefGoogle Scholar
  53. Rogan J, Ramírez M, Muñoz V, Valdivia JA, García G, Ramírez R, Kiwi M (2009) Diversity driven unbiased search of minimum energy cluster configurations. J Phys Condens Matter 21:084209CrossRefGoogle Scholar
  54. Rohlfing EA, Valentini JJ (1986) UV laser excited fluorescence spectroscopy of the jet-cooled copper dimer. J Chem Phys 84:6560–6566CrossRefGoogle Scholar
  55. Wang F, Liu W (2005) Benchmark four-component relativistic density functional calculations on Cu2, Ag2, and Au2. Chem Phys 311:63–69CrossRefGoogle Scholar
  56. Wang CS, Klein BM, Krakauer H (1985) Theory of magnetic and structural ordering in iron. Phys Rev Lett 54:1852–1855CrossRefGoogle Scholar
  57. Wang JL, Wang G, Chen X, Lu W, Zhao J (2002) Structure and magnetic properties of Co–Cu bimetallic clusters. Phys Rev B 66:014419CrossRefGoogle Scholar
  58. Wang H, Khait YG, Hoffmann MR (2005) Low-lying quintet states of the cobalt dimer. Mol Phys 103:263–268CrossRefGoogle Scholar
  59. Xiao JQ, Jiang JS, Chien CL (1992) Giant magnetoresistance in nonmultilayer magnetic systems. Phys Rev Lett 68:3749–3752CrossRefGoogle Scholar
  60. Yang M, Jackson KA, Koehler C, Frauenheim T, Jellinek J (2006) Structure and shape variations in intermediate-size copper clusters. J Chem Phys 124:024308CrossRefGoogle Scholar
  61. Zimmermann CG, Yeadon M, Nordlund K, Gibson JM, Averback RS, Herr U, Samwer K (1999) Burrowing of Co nanoparticles on clean Cu and Ag surfaces. Phys Rev Lett 83:1163–1166CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Marcos Pérez
    • 1
    • 2
  • Francisco Muñoz
    • 1
    • 2
  • José Mejía-López
    • 1
    • 2
  • Gerardo Martínez
    • 3
  1. 1.Facultad de FísicaPontificia Universidad Católica de ChileSantiagoChile
  2. 2.Center for the Development of Nanoscience and Nanotechnology (CEDENNA)SantiagoChile
  3. 3.Instituto de FísicaUniversidade Federal do Rio Grande do SulPorto Alegre, RSBrazil

Personalised recommendations