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Ghimire M.P.,Nepal Academy of Science and Technology | Ghimire M.P.,Condensed Matter Physics Research Center | Sandeep,Mizoram University | Sinha T.P.,Bose Institute of India | Thapa R.K.,Mizoram University
Journal of Alloys and Compounds | Year: 2011

The electronic density of states (DOS), magnetic moments and band structure of semi-Heusler alloy NiXSb (where X = Ti, V, Cr and Mn) has been studied by using the first principles full-potential linearized augmented plane wave method (FP-LAPW) based on density functional theory (DFT). For the exchange and correlation potential generalized-gradient approximation (GGA) is used. From the observations, NiTiSb shows the possibility of half-metallic ferromagnet (HMF) behavior with a band gap of 0.53 eV and an effective moment of 0.35 μB. The alloys like NiVSb, NiCrSb and NiMnSb are HMF with band gap of 0.49 eV, 0.38 eV and 0.48 eV and an effective moment of 1.995 μB, 3.01 μB and 3.99 μB respectively. DOS and band structure result shows the 3d states of Ni overlap with 3d states of X atoms suggesting hybridization between them. The exchange-splitting of Ni-3d and X-3d state electrons lead to localized spin moment which determines the HMF behavior of NiXSb. The results obtained are compared and found to be in close agreement with the available data. © 2011 Elsevier B.V. Source


Sandeep,Mizoram University | Ghimire M.P.,Nepal Academy of Science and Technology | Thapa R.K.,Mizoram University | Thapa R.K.,Condensed Matter Physics Research Center
Journal of Magnetism and Magnetic Materials | Year: 2011

The density of states (DOS) and the magnetic moments of SmCrSb3 and GdCrSb3 have been studied by first principles full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). For the exchange-correlation potential, the local-spin density approximations with correlation energy (LSDAU) method have been used. Total and partial DOS have been computed using the WIEN2k code. DOS result shows the exchange-splittings of Cr-3d and rare-earth (R) 4f states electrons, which are responsible for the ground state ferromagnetic (FM) behavior of the systems. The FM behavior of these systems is strongly influenced by the average number of Cr-3d and Sm (Gd) 4f-electrons. The effective moment of SmCrSb3 is found to be 7.07 μB while for GdCrSb3 it is 8.27 μB. The Cr atom plays a significant role on the magnetic properties due to the hybridization between Cr-3d and Sb-5p states. © 2011 Elsevier B.V. All rights reserved. Source


Chettri S.,Mizoram University | Rai D.P.,Pachhunga University College | Shankar A.,Mizoram University | Ghimire M.P.,Condensed Matter Physics Research Center | And 2 more authors.
Modern Physics Letters B | Year: 2016

In this paper, the structural, electronic and magnetic properties of Nd-doped rare earth aluminate, La1-xNdxAlO3 (x = 0%-100%) is studied using the first-principles full potential linearized augmented plane wave (FP-LAPW) method. The effects of partial Nd substitution for La in LaAlO3 are studied using supercell calculations. The electronic structure analysis indicates La1-xNdxAlO3 to be a probable half metal within the spin polarized generalized gradient approximation (GGA). The direct and indirect band gaps are reported and were analyzed as a function of concentration of Nd doping on LaAlO3. The calculated magnetic moments in La1-xNdxAlO3 were found to arise mainly from the Nd-4f electrons which manifest the magnetic nature of the system. The significant band gap narrowing with increase in doping concentration may find important applications in optoelectronic devices. © 2016 World Scientific Publishing Company. Source


Rai D.P.,Beijing Computational Science Research Center | Rai D.P.,Mizoram University | Shankar A.,Mizoram University | Ghimire M.P.,Japan International Center for Materials Nanoarchitectonics | And 2 more authors.
Computational Materials Science | Year: 2015

A density functional theory (DFT) employing generalized gradient approximation (GGA) and modified Becke Johnson (TB-mBJ) potential have been used to study the electronic, magnetic and optical properties of A2FeReO6 (AFRO). The presence of indirect band gap of majority electrons at EF and the conducting behaviour of minority electrons predicts these materials to be a half metallic ferrimagnets. The GGA band gaps are enhanced with the implementation of a new electron exchange semilocal potential called TB-mBJ. The real and imaginary parts of dielectric function, refractive index, absorption coefficient and reflectivity are calculated. The inter-band transitions to the optical properties are analyzed with the band structures. © 2015 Elsevier B.V. All rights reserved. Source


Sandeep,Mizoram University | Rai D.P.,Pachhunga University College | Rai D.P.,Beijing Computational Science Research Center | Shankar A.,Mizoram University | And 3 more authors.
Physica Scripta | Year: 2015

The electronic and magnetic properties of EuAlO3 are calculated by first-principles full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). The exchange and correlation potential is treated with different approximations: mBJ and GGA + U. Coulomb repulsion (U) has been calculated using super-cell calculations for EuAlO3. The GGA + U calculations reveal an indirect band gap of 4.6 eV for EuAlO3 in the spin down channel supporting the half metallic (HM) nature of the system. An effective integral magnetic moment also supported the HM nature of EuAlO3. © 2015 The Royal Swedish Academy of Sciences. Source

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