Ab initio calculations of structural, phonon and thermal properties of Co2MnGe and Co2MnSi

Document Type : Full length research Paper

Authors

Assistant Professor Of Physics,Department Of Physics, Rasht Branch, Islamic Azad University, Rasht, Iran

Abstract

In this paper, structural, phonon and thermal properties of Co2MnGe and Co2MnSi calculated and have been compared with each other. Structural properties of these alloys have a good agreement with other experimental and theoretical works. By using density functional perturbation theory and Quantum Espresso package, phonon dispersion calculation in different directions have been done. Calculation of total and partial phonon density of states demonstrated that by increasing of mass of atoms their contributions decrease at higher frequencies. Also, calculations of specific heat at constant volume and Debye temperature by quasi-harmonic Debye-Einstein model and GIBBS2 package have been performed by considering only phonon contribution in the temperatures range of 0K to 900K which have a good consistency with other theoretical works. Specific heat at low temperatures has T3 behavior, while it trend to saturation limit at high temperatures. Debye temperature decrease by increasing temperature slowly.

Keywords


 
[1] I. Galanakis, P.H. Dederichs(Eds), Half-Metallic Alloys Fundamentals and Applications, Springer, Berlin, Heidelberg, (2005).
[2] A. Bergmann, J. Grabis, B.P. Toperverg, V.Leiner,M.Wolff,H.Zabel,K.Westerholt, Antiferromagnetic dipolar ordering in [Co2MnGe/V]N multilayers. Physical Review B72(2005) 214403.
[3] S. Kämmerer, A. Thomas, A. Hütten, G. Reiss, Heusler alloy as magnetic electrodes in magnetic tunnel junctions Co2MnSi Heusler alloy as magnetic electrodes in magnetic tunnel junctions. Applied Physics Letters85(2004) 79.
[4] R.A.de Groot, F.M. Mueller, P.G. van Engen, K.H.J. Buschow, New Class of Materials: half-metallic ferromagnets. Physical Review Letters50(1983) 2024.
[5] J. Enkovaara, A. Ayuela, A.T. Zayak, P. Entel, L. Nordström, M. Dube, J. Jalkanen, J. Impola, R.M. Nieminen, Magnetically driven shape memory alloys. Materials Science and Engineering378(2004) 52–60.
[6] S. Picozzi, A. Continenza, A.J. Freeman, Co2MnX(X=Si,Ge,Sn) Heusler compounds: An ab initio study of their structural, electronic, and magnetic properties at zero and elevated pressure, Physical Review B66(2002) 94421.
[7] S. Ouardi, G.H. Fecher, B. Balke, A. Beleanu, X. Kozina G. Stryganyuk, C. Felser, W. Klob, H. Schrader, F. Bernardi, J. Morais, E. Ikenaga Y. Yamashita, S. Ueda, K. Kobayashi, Electronic and crystallographic structure, hard x-ray photoemission, and mechanical and transport properties of the half-metallic Heusler compound Co2MnGe. Physical Reiew B84(2011) 155122.
[8] A. Candan, G.Ugur, Z. Charifi, H. Baaziz, M.R. Ellialtioglu. Electronic structure and vibrational properties in cobalt-based full-Heusler compounds : A first principle study of Co2MnX(X=Si,Ge,Al,Ga), Journal of Alloys and Compounds560(2013) 215–222.
[9] M. Ito, T. Furuta, K.Kai, A.Taira, K. Onda, I.Shigeta, M.Hiroi Thermodynamic Properties of Heusler Fe2−xCoxMnSi, Journal of Magnetism and Magnetic Materials428(2017) 390–393.
[10] P. Giannozzi, S. Baroni, N. Bonini, M. Calandra, R. Car, C. Cavazzoni, D. Ceresoli, G.L. Chiarotti, M. Cococcioni, I. Dabo, A. Dal Corso, S. de Gironcoli, S. Fabris, G. Fratesi, R. Gebauer, U. Gerstmann, C. Gougoussis, A. Kokalj, M. Lazzeri, L. Martin-Samos, N. Marzari, F. Mauri, R. Mazzarello, S. Paolini, A. Pasquarello, L. Paulatto, C. Sbraccia, S. Scandolo, G. Sclauzero, A.P. Seitsonen, A. Smogunov, P. Umari, R.M. Wentzcovitch, QUANTUM ESPRESSO  package:www.quantum-espresso.org
[11] A. Otero-de-la-Roza, V. Luaña, Gibbs 2 : A new version of the quasi-harmonic model code. I. Robust treatment of the static data. Computer Physics Communications182(2011) 1708–1720.
[12] A. Otero-de-la-Roza, D .Abbasi-pérez,V. Luana, GIBBS2: A new Version of the quasiharmonic model code.II. Models for Solid-State thermodynamics, features and implementation. Computer Physics Communications182(2011) 2232–2248.
[13] J.P. Perdew, K. Burke, M. Ernzerhof, Generalized Gradient Approximation Made Simple, Physical Review Letters 77 (1996) 3865-3868.
[14] ع. فاضلی کیسمی، ج. موسوی، محاسبات ابتدابه‌ساکن خواص ساختاری، گذار فاز، فونونی و خواص ترمودینامیکی AlAs، نشریة پژوهش سیستم‌های بس‌ذره‌ای، 6 (1395) 59-65.
[15] P. J.WEBSTER, Magneticand chemicalorderin Heusleralloyscontaining Cobaltand Manganes. Journal of Physics Chemistry of Solids32(1971)1221.
[16] H. Joshi, D.P. Rai, Sandeep, R.K. Thapa, Electronic structure and thermoelectric property of Co2YGe (Y= Mn, Fe) Heusler compounds : a first principle study. Journal of Physics: Conference Series765(2016) 012010.
[17] S. Amari, R. Mebsout, S. Méçabih, B.Abbar, B. Bouhafs, First-principle study of magnetic, elastic and thermal properties of full Heusler Co2MnSi, Intermetallics44 (2014) 26-30