Structural variants and the modified Slater-Pauling curve for transition-metal-based half-Heusler alloys

2013 ◽  
Vol 113 (4) ◽  
pp. 043709 ◽  
Author(s):  
M. Shaughnessy ◽  
L. Damewood ◽  
C. Y. Fong ◽  
L. H. Yang ◽  
C. Felser
Keyword(s):  
Transition Metal ◽  
Heusler Alloys ◽  
Structural Variants

Impurities in Magnetic Materials Studied by PAC Spectroscopy

2011 ◽  
Vol 311 ◽  
pp. 39-61 ◽  
Author(s):  
Artur Wilson Carbonari ◽  
José Mestnik-Filho ◽  
Rajendra Narain Saxena
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Magnetic Fields ◽  
Rare Earth Elements ◽  
Magnetic Hyperfine Field ◽  
Heusler Alloys ◽  
Local Fields ◽  
Pac Spectroscopy ◽  
Open Issue ◽  
Local Magnetic Fields

Perturbed gamma-gamma angular correlation (PAC) spectroscopy is a precise and highly efficient tool to follow the temperature dependence of local magnetic fields in any material. Its resolution and efficiency does not depend on temperature and therefore can measure local fields at low as well as high temperature with the same accuracy. Due its versatility in using different probe nuclei it can sense the local magnetic fields at different sites in the crystalline structure of materials. In this review, important results obtained with PAC spectroscopy are shown in two classes of materials: transition metal and transition-metal based compounds and rare earth elements and rare-earth-element based compounds using mainly three different probe nuclei:111Cd,181Ta and140Ce. PAC spectroscopy has contributed to the systematic study of the magnetic hyperfine field in impurities in matrices of Fe, Co and Ni as well as in transition-metal based Heusler alloys. It has also provided important contribution to the investigation of magnetism in rare-earth elements and intermetallic compounds. An still open issue concerning the local fields in metallic magnetic compounds and elements is the exchange interaction between the magnetic ions of the host and a dilute magnetic impurity, which acts as a defect in the magnetic lattice. PAC spectroscopy has been contributing to study this problem with success. Also shown in this review is the crucial role of ab-initio first principle calculations in the interpretation of PAC results.

Combinatorial Investigation of Spintronic Materials

MRS Bulletin ◽  
2003 ◽  
Vol 28 (10) ◽  
pp. 734-739 ◽  
Author(s):  
Y. Matsumoto ◽  
H. Koinuma ◽  
T. Hasegawa ◽  
I. Takeuchi ◽  
F. Tsui ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Room Temperature ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Magnetic Transition ◽  
Heusler Alloys ◽  
Oxide Systems ◽  
Diluted Magnetic

AbstractHigh-throughput synthesis and characterization techniques have been effective in discovering new materials and performing rapid mapping of phase diagrams. The application of the combinatorial strategy to explore doped transition-metal oxides has led to the discovery of a transparent room-temperature ferromagnetic oxide in Co-doped anatase TiO2. The discovery has triggered a wave of studies into other metal oxide systems in pursuit of diluted magnetic semiconductors. In this article, we describe recent combinatorial studies of magnetic transition-metal oxides, germanium-based magnetic semiconductors, and Heusler alloys.

scholarly journals Comprehensive DFT investigation of transition-metal-based new quaternary Heusler alloys CoNbMnZ (Z = Ge, Sn): compatible for spin-dependent and thermoelectric applications

RSC Advances ◽  
2020 ◽  
Vol 10 (71) ◽  
pp. 43870-43881
Author(s):  
Ab Quyoom Seh ◽  
Dinesh C. Gupta
Keyword(s):  
Transition Metal ◽  
Heusler Alloys ◽  
Quaternary Heusler Alloys

Possible d–d hybridization for characterizing the electronic profile of the materials.

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

Problems with oxygen analysis in the system MgO-Al2O3-SiO2 with the electron microprobe

1992 ◽  
Vol 50 (2) ◽  
pp. 1624-1625
Author(s):  
Michel Fialin ◽  
Guy Rémond
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Electrostatic Charge ◽  
Carbon Layer ◽  
Sample Holder ◽  
Rock Matrix ◽  
Electrical Discharges ◽  
Thin Carbon ◽  
Beam Instabilities

Oxygen-bearing minerals are generally strong insulators (e.g. silicates), or if not (e.g. transition metal oxides), they are included within a rock matrix which electrically isolates them from the sample holder contacts. In this respect, a thin carbon layer (150 Å in our laboratory) is evaporated on the sections in order to restore the conductivity. For silicates, overestimated oxygen concentrations are usually noted when transition metal oxides are used as standards. These trends corroborate the results of Bastin and Heijligers on MgO, Al2O3 and SiO2. According to our experiments, these errors are independent of the accelerating voltage used (fig.l).Owing to the low density of preexisting defects within the Al2O3 single-crystal, no significant charge buildup occurs under irradiation at low accelerating voltage (< 10keV). As a consequence, neither beam instabilities, due to electrical discharges within the excited volume, nor losses of energy for beam electrons before striking the sample, due to the presence of the electrostatic charge-induced potential, are noted : measurements from both coated and uncoated samples give comparable results which demonstrates that the carbon coating is not the cause of the observed errors.

Electron energy loss near edge structures of intermetallic alloys and grain boundaries in NiAl

1996 ◽  
Vol 54 ◽  
pp. 522-523
Author(s):  
G.A. Botton ◽  
C.J. Humphreys
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Energy Loss ◽  
Grain Boundaries ◽  
Industrial Applications ◽  
Edge Structure ◽  
Structural Applications ◽  
Yield Behaviour ◽  
Late Transition ◽  
Metal Aluminides

Transition metal aluminides are of great potential interest for high temperature structural applications. Although these materials exhibit good mechanical properties at high temperature, their use in industrial applications is often limited by their intrinsic room temperature brittleness. Whilst this particular yield behaviour is directly related to the defect structure, the properties of the defects (in particular the mobility of dislocations and the slip system on which these dislocations move) are ultimately determined by the electronic structure and bonding in these materials. The lack of ductility has been attributed, at least in part, to the mixed bonding character (metallic and covalent) as inferred from ab-initio calculations. In this work, we analyse energy loss spectra and discuss the features of the near edge structure in terms of the relevant electronic states in order to compare the predictions on bonding directly with spectroscopic experiments. In this process, we compare spectra of late transition metal (TM) to early TM aluminides (FeAl and TiAl) to assess whether differences in bonding can also be detected. This information is then discussed in terms of bonding changes at grain boundaries in NiAl.

A new lithium diffusion model in layered oxides based on asymmetric but reversible transition metal migration

2020 ◽  
Vol 13 (4) ◽  
pp. 1269-1278 ◽  
Author(s):  
Kyojin Ku ◽  
Byunghoon Kim ◽  
Sung-Kyun Jung ◽  
Yue Gong ◽  
Donggun Eum ◽  
...  
Keyword(s):  
Transition Metal ◽  
Diffusion Model ◽  
Layered Oxides ◽  
Layered Oxide ◽  
Reversible Transition ◽  
Lithium Diffusion ◽  
Metal Migration

We propose a new lithium diffusion model involving coupled lithium and transition metal migration, peculiarly occurring in a lithium-rich layered oxide.

Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes

2020 ◽  
Vol 7 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Jingqi Han ◽  
Kin-Man Tang ◽  
Shun-Cheung Cheng ◽  
Chi-On Ng ◽  
Yuen-Kiu Chun ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Carbene Complexes ◽  
New Class

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

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