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Stabilization mechanism of γ-Mg₁₇Al₁₂ and β-Mg₂Al₃ complex metallic alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:425703. [PMID: 24080784 DOI: 10.1088/0953-8984/25/42/425703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Large-unit-cell complex metallic alloys (CMAs) frequently achieve stability by lowering the kinetic energy of the electron system through formation of a pseudogap in the electronic density of states (DOS) across the Fermi energy εF. By employing experimental techniques that are sensitive to the electronic DOS in the vicinity of εF, we have studied the stabilization mechanism of two binary CMA phases from the Al-Mg system: the γ-Mg17Al12 phase with 58 atoms in the unit cell and the β-Mg2Al3 phase with 1178 atoms in the unit cell. Since the investigated alloys are free from transition metal elements, orbital hybridization effects must be small and we were able to test whether the alloys obey the Hume-Rothery stabilization mechanism, where a pseudogap in the DOS is produced by the Fermi surface-Brillouin zone interactions. The results have shown that the DOS of the γ-Mg17Al12 phase exhibits a pronounced pseudogap centered almost exactly at εF, which is compatible with the theoretical prediction that this phase is stabilized by the Hume-Rothery mechanism. The disordered cubic β-Mg2Al3 phase is most likely entropically stabilized at high temperatures, whereas at lower temperatures stability is achieved by undergoing a structural phase transition to more ordered rhombohedral β' phase at 214 ° C, where all atomic sites become fully occupied. No pseudogap in the vicinity of εF was detected for the β' phase on the energy scale of a few 100 meV as determined by the 'thermal observation window' of the Fermi-Dirac function, so that the Hume-Rothery stabilization mechanism is not confirmed for this compound. However, the existence of a much broader shallow pseudogap due to several critical reciprocal lattice vectors [Formula: see text] that simultaneously satisfy the Hume-Rothery interference condition remains the most plausible stabilization mechanism of this phase. At Tc = 0.85 K, the β' phase undergoes a superconducting transition, which slightly increases the cohesive energy and may contribute to relative stability of this phase against competing neighboring phases.
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Hume-Rothery stabilization mechanism and e/a determination for RT- and MI-type 1/1-1/1-1/1 approximants studied by FLAPW-Fourier analyses. Chem Soc Rev 2012; 41:6799-820. [DOI: 10.1039/c2cs35161g] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fermi surface-Brillouin-zone-induced pseudogap in γ-Mg17Al12 and a possible stabilization mechanism of β-Al3Mg2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:485501. [PMID: 21406747 DOI: 10.1088/0953-8984/22/48/485501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The electronic structure of γ phase in the system Mg(17)Al(12) containing 58 atoms per unit cell with space group I43m has been calculated by using the WIEN2k-FLAPW program package. A pseudogap is found across the Fermi level. The FLAPW-Fourier spectra at the symmetry points N and Γ of the bcc Brillouin zone revealed that electronic states across the Fermi level at these symmetry points are dominated by |G|(2) = 26 and 24 states corresponding to centers of {510} + {431} and {422} zone planes, respectively. The 1253-wave nearly-free-electron (NFE) band calculations identified that a combination of the two Fermi surface-Brillouin-zone (FsBz) interactions associated with |G|(2) = 26 and 24 account well for the observed DOS pseudogap in γ-Mg(17)Al(12), most likely leading to the stabilization of this complex metallic compound. The β-Al(3)Mg(2) containing 1178 atoms per cubic unit cell is suggested to be stabilized by satisfying the Hume-Rothery matching condition expressed in terms of e/uc, the number of electrons per unit cell, versus critical |G|(2). A critical |G|(2) is predicted to be 200 in β-Al(3)Mg(2), which results in 84 Brillouin zone planes interacting almost simultaneously with a more or less spherical Fermi surface.
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Failure of the Hume-Rothery stabilization mechanism in the Ag(5)Li(8) gamma-brass studied by first-principles FLAPW electronic structure calculations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:275228. [PMID: 21694389 DOI: 10.1088/0953-8984/20/27/275228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The first-principles FLAPW (full potential linearized augmented plane wave) electronic structure calculations were performed for the Ag(5)Li(8) gamma-brass, which contains 52 atoms in a unit cell and has been known for many years as one of the most structurally complex alloy phases. The calculations were also made for its neighboring phase AgLi B2 compound. The main objective in the present work is to examine if the Ag(5)Li(8) gamma-brass is stabilized at the particular electrons per atom ratio e/a = 21/13 in the same way as some other gamma-brasses like Cu(5)Zn(8) and Cu(9)Al(4), obeying the Hume-Rothery electron concentration rule. For this purpose, the e/a value for the Ag(5)Li(8) gamma-brass as well as the AgLi B2 compound was first determined by means of the FLAPW-Fourier method we have developed. It proved that both the gamma-brass and the B2 compound possess an e/a value equal to unity instead of 21/13. Moreover, we could demonstrate why the Hume-Rothery stabilization mechanism fails for the Ag(5)Li(8) gamma-brass and proposed a new stability mechanism, in which the unique gamma-brass structure can effectively lower the band-structure energy by forming heavily populated bonding states near the bottom of the Ag-4d band.
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Amorphization process induced by mechanical alloying in the immiscible Cu-Ta system. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/bf02667804] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Effects of Secondary Structures of Heated Egg White Protein on the Binding Between Prime Starch and Tailings Fractions in Fresh Wheat Flour. Cereal Chem 2004. [DOI: 10.1094/cchem.2004.81.5.633] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Magnetic circular dichroism at transition metal L2,3 edges in D03-type (Fe(1-x)Vx)3Al alloys. JOURNAL OF SYNCHROTRON RADIATION 2001; 8:457-459. [PMID: 11512813 DOI: 10.1107/s0909049500016927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2000] [Accepted: 11/10/2000] [Indexed: 05/23/2023]
Abstract
Magnetic circular dichroism (MCD) spectra have been measured at the Fe and V L2,3 edges of DO3-type (Fe(1-x)Vx)3Al in order to investigate their local magnetic moments and electronic structures. Large MCD is observed at the Fe L2,3 edges, while the V L2,3 MCD shows relatively small intensity with complicated features. Signs of these MCD spectra indicate an antiferromagnetic coupling between the magnetic moments on Fe and V. According to the analysis based on the magneto-optical sum rules, the magnetic moment decreases with x, but remains fairly large for Fe2VAl, which might arise from its marginally magnetic nature.
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Magnetic circular dichroism at transition metal L2,3 edges in D03-type (Fe(1-x)Mn(x))3Al alloys. JOURNAL OF SYNCHROTRON RADIATION 2001; 8:455-456. [PMID: 11512812 DOI: 10.1107/s0909049500016873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2000] [Accepted: 11/09/2000] [Indexed: 05/23/2023]
Abstract
We have measured magnetic circular dichroism (MCD) spectra at the transition-metal L2,3 edges in D03-type (Fe(1-x)Mn(x))3Al in order to investigate their local magnetic moments. The analysis of the spectra shows that Fe has moments much larger than Mn, whose moment is ferromagnetically coupled with the Fe one. This does not lend support to the antiferromagnetic mechanism proposed for the reduction in magnetization as well as a large Mn moment predicted for x = 1/3. The evolution of satellites found in the Mn spectrum with x increased suggests that the change in the electronic state may result in the magnetization reduction.
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Influence of deformation on the low-temperature specific heat of a dilute α phase Pd-H alloy. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0305-4608/7/3/002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Anisotropic optical spectra of PrBa2Cu4O8: possible Tomonaga-Luttinger liquid response of the quasi-one-dimensional metallic CuO double chains. PHYSICAL REVIEW LETTERS 2000; 85:5428-5431. [PMID: 11136013 DOI: 10.1103/physrevlett.85.5428] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2000] [Indexed: 05/23/2023]
Abstract
The optical spectra of PrBa2Cu4O8 show large in-plane anisotropy. For the a polarization (E perpendicular chain), the spectrum is characterized by a gap of 1.4 eV, indicating the charge-transfer insulating nature of the CuO2 planes. For the metallic chain direction (E // b), the spectrum deviates from a simple Drude response; reflectivity R(b)(omega) shows a sharp edge at approximately 1 eV but it also shows a dip at approximately 15 meV, which splits the conductivity spectrum into two parts--a zero-energy mode with small weight and a pronounced 40 meV mode. These features are discussed in terms of a Tomonaga-Luttinger liquid in a doped 1D Mott insulator and compared with 1D Bechgaard salts.
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Low-temperature lattice specific heats of an amorphous Pd-Si alloy subjected to various heat treatments. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/10/6/009] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Low-temperature specific heat measurements of simple divalent amorphous Mg0.7Zn0.3alloy. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/11/7/012] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Experimental test of the extended Ziman theory, using free electron-like Ag-Cu based amorphous alloys. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/12/10/023] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Electron transport properties of amorphous Mg-Zn alloys with different Zn compositions. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/12/9/010] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Formation and low-temperature electronic properties of liquid-quenched Ag-Cu-X (X=Mg, Si, Sn and Sb) metallic glasses. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/14/5/014] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Low-temperature specific heat and soft X-ray spectroscopic studies of Ni33Zr67-based metallic glasses containing H, B, Al and Si. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/17/11/019] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Interplay of the Boltzmann-type ordinary transport and quantum corrections in Ag-Cu-Ge amorphous alloy system. II. Temperature dependence of Hall coefficient. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/18/9/019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Studies of negative TCR and electronic structure of nonmagnetic metallic glasses based on Y and La. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/17/1/019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Electron transport studies of Ni33Zr67-based metallic glasses containing H, B, Al and Si. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/17/11/020] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Low temperature specific heat, magnetic susceptibility and electrical resistivity measurements in Ni-Ti metallic glasses. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/18/1/012] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Interplay of the Boltzmann-type ordinary transport and quantum corrections in Ag-Cu-Ge amorphous alloy system. I. Temperature dependence of electrical resistivity. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/18/9/018] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Pseudogap formation in the intermetallic compounds (Fe1-xVx)3Al. PHYSICAL REVIEW LETTERS 2000; 84:3674-3677. [PMID: 11019174 DOI: 10.1103/physrevlett.84.3674] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/1999] [Indexed: 05/23/2023]
Abstract
Optical conductivity data of the intermetallic compounds (Fe1-xVx)3Al ( 0</=x</=0.33) reveal that their density of states around the Fermi energy ( E(F)) is strongly reduced as x is increased. In particular, Fe2VAl ( x = 0.33) has a deep, well-developed pseudogap of 0.1-0.2 eV at E(F) and a small density ( approximately 5x10(20) cm(-3)) of carriers, which is highly unusual for intermetallic compounds. It is shown that the pseudogap results from the band structure of Fe2VAl, rather than from temperature-dependent correlation effects. Based on the present results, we propose a simple model that consistently explains both the semiconductorlike transport and the metallic photoemission results previously observed for Fe2VAl.
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Structure of liquid carbon tetrachloride up to the subcritical point measured by wide Q-range neutron diffraction. J Chem Phys 1997. [DOI: 10.1063/1.475051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Experimental studies of atomic structure, electronic structure, and the electronic transport mechanism in amorphous Al-Cu-Y and Mg-Cu-Y ternary alloys. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:3200-3210. [PMID: 9986219 DOI: 10.1103/physrevb.54.3200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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37
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Electronic structure, electron transport properties, and relative stability of icosahedral quasicrystals and their 1/1 and 2/1 approximants in the Al-Mg-Zn alloy system. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:9300-9309. [PMID: 9979974 DOI: 10.1103/physrevb.52.9300] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Mechanical Alloying in Cu–V and Cu–Ta Systems Characterized by Positive Heat of Mixing ( Overview). ACTA ACUST UNITED AC 1995. [DOI: 10.2320/matertrans1989.36.210] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Magnetic, electronic, and electron-transport properties of amorphous (Co0.85B0.15)100-xXx (X=B, Al, Si, and V) alloys. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:2678-2688. [PMID: 10006325 DOI: 10.1103/physrevb.47.2678] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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40
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Electronic structure and magnetism of amorphous Co1-xBx alloys. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:2671-2677. [PMID: 10006324 DOI: 10.1103/physrevb.47.2671] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Formation of Quasicrystals and Approximant Crystals by Mechanical Alloying in Mg–Al–Zn Alloy System. ACTA ACUST UNITED AC 1993. [DOI: 10.2320/matertrans1989.34.102] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Extended x-ray-absorption fine-structure studies on ball-milled powders of the immiscible system Cu-V. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:5711-5714. [PMID: 10004359 DOI: 10.1103/physrevb.46.5711] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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On the Negative TCR Phenomena in Non-Magnetic Metallic Glasses*. Z PHYS CHEM 1988. [DOI: 10.1524/zpch.1988.157.part_2.711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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45
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Magnetic susceptibility and 31P nuclear magnetic resonance study of the electronic structure of amorphous and crystalline NiCuP alloys. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0025-5416(88)90344-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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46
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Electronic structure of (Ni33Zr67)1 − 1Xx (X ≡ Ti, V, Cr, Mn, Fe, Co, Ni or Cu) ternary metallic glasses studied by low temperature specific heat measurements. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0025-5416(88)90342-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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47
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