In this study, we have investigated the structural, electronic, magnetic and elastic properties of the full-Heusler Cr 2 MnAl alloy in the framework of density functional theory with generalized gradient approximation (GGA). The calculated results showed that Cr 2 MnAl was stable in ferrimagnetic configuration and crystallized in the Hg 2 CuTitype structure. From the band structure and density of states calculation results, we concluded that Cr 2 MnAl belongs to a kind of half-metallic compound with an indirect band gap of 0.37 eV. Immediately thereafter, we have analyzed the origin of half-metallic band gap. The total magnetic moment of Cr 2 MnAl at the stable state is −2 µ B per formula unit, obeying the Slater-Pauling rule Mt = Zt −24. In addition, various mechanical properties have been obtained and discussed based on the three principle elastic tensor elements C 11 , C 12 and C 44 for the first time in the present work. We expect that our calculated results may trigger the application of Cr 2 MnAl in future spintronics field.Mod. Phys. Lett. B Downloaded from www.worldscientific.com by GEORGETOWN UNIVERSITY on 08/21/15. For personal use only. S. Qi et al.observed theoretically or experimentally for half-metallic properties, for example, double perovskites, 6 some oxides, 7,8 dilute magnetic semiconductor 9,10 and materials possessing zincblende structure. 11,12 In fact, investigating and searching for new half-metallic materials are mostly focused on the Heusler alloys due to their diverse physical properties. [13][14][15] Generally, the class of ternary Heusler alloy family includes two possible variations, called half-Heusler and full-Heusler alloy, with chemical formula XYZ and X 2 Y Z, respectively. X and Y represent different transition elements, while Z refers to the main group III, IV or V element. The full-Heusler alloy crystallizes either in the Cu 2 MnAl prototype (space group Fm3(−)m) or in the Hg 2 CuTi prototype (space group F4(−)3m) 16 known as inverse Heusler structure. In the case when the number of 3d valence electrons of Y atom is larger than that of X in full-Heusler alloy, the later structure will be preferred.The first-principles calculation plays a key role due to the fact that many alloys have been initially predicted before their synthesis and integration in realistic devices. Based on the electronic calculations, many Heusler alloys have been predicted half-metallic compounds. Galanakis et al. studied Cr 2 MnZ (Z = P, As, Sb, and Bi) alloys 17 with exactly 24 valence electrons using ab initio electronic structure calculations, and they predicted Cr 2 MnSb as half-metallic fully compensated ferrimagnets (FCFs) with the Curie temperature 342 K. Li et al. investigated the full-Heusler alloys Cr 2 VX (X = Ga, Si, Ge, Sb) 18 and revealed that Cr 2 VSb exhibited a half-metallic nature, yet Cr 2 VSi and Cr 2 VGe showed nearly half-metallic ferromagnetism. Singh et al. studied Cr 2−x Fe x CoAl and Cr 2−x Fe x CoSi to gain 100% spin-polarization. 19 Recently, Skaftouros 20 has proposed Cr 2 Z...

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The elastic and thermal properties of ScRu under pressure are studied using a first-principles pseudopotential method within the generalized gradient approximation. The calculated lattice parameter and formation enthalpy are in good agreement with the previous experimental and theoretical results. From the static finite strain technique, we obtained three independent elastic constants (C 11 , C 12 and C 44 ) and various secondary elasticity parameters such as shear modulus, Young's modulus and elastic anisotropy, as functions of pressure. This study also provided the pressure and temperature variations of the bulk modulus, Debye temperature, thermal expansion coefficient and heat capacity in wide pressure (0-60 GPa) and temperature (0-1800 K) ranges.

The magnetic and magnetoelastic properties of have been investigated. The stable single Laves phase is synthesized at ambient pressure for . The successful formation of this Laves phase can be ascribed to the strong Ce 4f bonding. Spin reorientation is observed around 150 K for Nd stoichiometric concentrations above 0.2. The lattice parameter, Curie temperature, low-temperature saturation magnetization and room-temperature anisotropic magnetostriction all increase with the Nd concentration. This indicates that the effect of the Ce ion is only dilution of the magnetism. is ferromagnetic with an estimated magnetic moment of per formula unit, a Curie temperature of 589 K and a room-temperature magnetostriction coefficient of 420 ppm. The largest saturation magnetostriction 320 ppm, is obtained at x = 0.2. No apparent evidence of Ce ions changing their valence was observed.

The thermal properties of TiN -based nitrides are studied using first-principles calculations. Bulk modulus, thermal expansion, heat capacity, vibrational entropy and melting point for TiN –X compounds are computed, considering all possible transition-metal solute species X. The calculated properties show clear trends as a function of d-band filling. The results indicate that the largest increase of melting point of TiN is caused by alloying element W. Computed thermal properties for pure TiN are in good agreement with the available experimental and theoretical data.