Are half-metallic ferromagnets half metals? (invited)

Dowben, Peter A.; Skomski, Ralph

doi:10.1063/1.1682911

Cited by 132 publications

(120 citation statements)

References 102 publications

Supporting

Mentioning

116

Contrasting

Order By: Relevance

“…If U 10 is applied, then the spin polarization at F is 75%, a value that is compatible to the approximately 55% found in [67]. This indicates that on-site correlation might be one more reason why no complete spin polarization was found in this compound (for others, see [75]). …”

Section: The Role Of Correlation In the Heusler Compounds Co 2 Mnsi Asupporting

confidence: 56%

Rational design of new materials for spintronics: Co₂FeZ (Z=Al, Ga, Si, Ge)

Balke

Wurmehl

Fecher

et al. 2008

Science and Technology of Advanced Materials

171

View full text Add to dashboard Cite

Spintronic is a multidisciplinary field and a new research area. New materials must be found for satisfying the different types of demands. The search for stable half-metallic ferromagnets and ferromagnetic semiconductors with Curie temperatures higher than room temperature is still a challenge for solid state scientists. A general understanding of how structures are related to properties is a necessary prerequisite for material design. Computational simulations are an important tool for a rational design of new materials. The new developments in this new field are reported from the point of view of material scientists. The development of magnetic Heusler compounds specifically designed as material for spintronic applications has made tremendous progress in the very recent past. Heusler compounds can be made as half-metals, showing a high spin polarization of the conduction electrons of up to 100% in magnetic tunnel junctions. High Curie temperatures were found in Co 2 -based Heusler compounds with values up to 1120 K in Co 2 FeSi. The latest results at the time of writing are a tunnelling magnet resistance (TMR) device made from the Co 2 FeAl 0.5 Si 0.5 Heusler compound and working at room temperature with a (TMR) effect higher than 200%. Good interfaces and a well-ordered compound are the precondition to realize the predicted half-metallic properties. The series Co 2 FeAl 1−x Si x is found to exhibit half-metallic ferromagnetism over a broad range, and it is shown that electron doping stabilizes the gap in the minority states for x = 0.5. This might be a reason for the exceptional temperature behaviour of Co 2 FeAl 0.5 Si 0.5 TMR devices.Using x-ray diffraction (XRD), it was shown conclusively that Co 2 FeAl crystallizes in the B2 structure whereas Co 2 FeSi crystallizes in the L2 1 structure. For the compounds Co 2 FeGa or Co 2 FeGe, with Curie temperatures expected higher than 1000 K, the standard XRD technique using laboratory sources cannot be used to easily distinguish between the two structures. For this reason, the EXAFS technique was used to elucidate the structure of these two compounds. Analysis of the data indicated that both compounds crystallize in the L2 1 structure which makes these two compounds suitable new candidates as materials in magnetic tunnel junctions.

show abstract

Section: The Role Of Correlation In the Heusler Compounds Co 2 Mnsi Asupporting

confidence: 56%

Rational design of new materials for spintronics: Co₂FeZ (Z=Al, Ga, Si, Ge)

Balke

Wurmehl

Fecher

et al. 2008

Science and Technology of Advanced Materials

171

View full text Add to dashboard Cite

show abstract

“…This attraction remains in spite of the growing recognition that true half-metallic character may not be possible at fi nite temperatures [1,2] due to magnons [1][2][3][4][5] as well as zero-temperature interactions [6,7]. Experimental data on band structure are available for very few nominally half-metallic systems, such as NiMnSb [8].…”

Section: Introductionmentioning

confidence: 99%

“…Experimental data on band structure are available for very few nominally half-metallic systems, such as NiMnSb [8]. These studies have been largely limited by experimental diffi culties in preparing a surface suitable for photoemission [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…CoS 2 can be alloyed with the narrow band gap semiconductor FeS 2 to become the highly spin-polarized ferromagnet Fe 1−x Co x S 2 , which more closely resembles an ideal ground-state half-metallic ferromagnet, by "tuning" the Fermi level [12][13][14]19]. The problem with Fe 1−x Co x S 2 is that these systems will likely suffer from Co segregation [20], making the surface unstable, as is observed for many other nominally half-metallic systems [1,2].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The electronic band structure of CoS₂

Wu¹,

Losovyj²,

Wisbey³

et al. 2007

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Manno, M.; Wang, L.; Leighton, C.; and Dowben, Peter A., "The electronic band structure of CoS 2 " (2007 AbstractAngle-resolved and energy-dependent photoemission was used to study the band structure of paramagnetic CoS 2 from high-quality single-crystal samples. A strongly dispersing hybridized Co-S band is identifi ed along the Γ-X line. Fermi level crossings are also analyzed along this line, and the results are interpreted using band structure calculations. The Fermi level crossings are very sensitive to the separation in the S-S dimer, and it is suggested that the half-metallic gap in CoS 2 may be controlled by the bondingantibonding splitting in this dimer, rather than by exchange splitting on the Co atoms.

show abstract

“…The electronic structures of nominally half-metallic systems are, nonetheless of considerable interest as an avenue for studying the interplay between high polarization and band structure. Their attraction remains in spite of the growing recognition that true half-metallic character is unlikely to be ever demonstrated at fi nite temperatures, due to magnons [4,5], as well as zero-temperature interactions [6,7]. It is natural, therefore, to explore the rareearth compounds, as rare-earth elements generally have much larger magnetic moments and demonstrate some fascinating phenomena [8,9].…”

Section: Introductionmentioning

confidence: 99%

Electronic, Magnetic and Transport Properties of Rare‐Earth Monopnictides

Duan¹,

Sabirianov²,

Mei³

et al. 2007

ChemInform

Self Cite

View full text Add to dashboard Cite

The electronic structures and magnetic properties of many rare-earth monopnictides are reviewed in this article. Possible candidate materials for spintronics devices from the rare-earth monopnictide family, i.e. high polarization (nominally half-metallic) ferromagnets and antiferromagnets, are identifi ed. We attempt to provide a unifi ed picture of the electronic properties of these strongly correlated systems. The relative merits of several ab initio theoretical methods, useful in the study of the rare-earth monopnictides, are discussed. We present our current understanding of the possible half-metallicity, semiconductor-metal transitions, and magnetic orderings in the rare-earth monopnictides. Finally, we propose some potential strategies to improve the magnetic and electronic properties of these candidate materials for spintronics devices.

show abstract

Are half-metallic ferromagnets half metals? (invited)

Cited by 132 publications

References 102 publications

Rational design of new materials for spintronics: Co₂FeZ (Z=Al, Ga, Si, Ge)

Rational design of new materials for spintronics: Co₂FeZ (Z=Al, Ga, Si, Ge)

The electronic band structure of CoS₂

Electronic, Magnetic and Transport Properties of Rare‐Earth Monopnictides

Contact Info

Product

Resources

About

Are half-metallic ferromagnets half metals? (invited)

Cited by 132 publications

References 102 publications

Rational design of new materials for spintronics: Co2FeZ (Z=Al, Ga, Si, Ge)

Rational design of new materials for spintronics: Co2FeZ (Z=Al, Ga, Si, Ge)

The electronic band structure of CoS2

Electronic, Magnetic and Transport Properties of Rare‐Earth Monopnictides

Contact Info

Product

Resources

About

Rational design of new materials for spintronics: Co₂FeZ (Z=Al, Ga, Si, Ge)

Rational design of new materials for spintronics: Co₂FeZ (Z=Al, Ga, Si, Ge)

The electronic band structure of CoS₂