Magnetic and electronic properties of a single crystal of ordered double perovskite<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">FeMoO</mml:mi></mml:mrow><mml:mrow><mml:mn>6</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Tomioka, Y.; Okuda, Takashi; Okimoto, Y.; Kumai, Reiji; Kobayashi, Kojiro; Tokura, Y.

doi:10.1103/physrevb.61.422

Cited by 454 publications

(319 citation statements)

References 12 publications

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“…While the bulk of these materials is metallic, as confirmed by their metalliclike thermopower [12], the zero-field conductivities (σ(T)) of polycrystalline samples are non-metallic (the conductivity increases with increasing T). Metallic-like resistivity was found in a single crystal of SFMO [13]. conductivity over the same range of T, for some samples of SCMO [14].…”

Section: Inter-grain Tunnelling In Sr 2 Bb'omentioning

confidence: 78%

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Inter-grain tunnelling in the half-metallic double-perovskites Sr₂BB'O₆(BB'= FeMo, FeRe, CrMo, CrW, CrRe)

Fisher

Genossar

Chashka

et al. 2014

EPJ Web of Conferences

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Abstract. The zero-field conductivities (σ) of polycrystalline title materials, are governed by intergrain transport. In the majority of cases their σ(T) can be described by the "fluctuation induced tunnelling" model. Analysis of the results in terms of this model reveals two remarkable features: 1. For all Sr2FeMoO6 samples of various microstructures, the tunnelling constant (barrier width × inverse decay-length of the wave-function) is ~ 2, indicating the existence of an intrinsic insulating boundary layer with a well-defined electronic (and magnetic) structure. 2. The tunnelling constant for all cold-pressed samples decreases linearly with increasing magnetic-moment/formula-unit.

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Section: Inter-grain Tunnelling In Sr 2 Bb'omentioning

confidence: 78%

“…The conductivities of the samples at T=0 (σ(0)), spread over many orders of magnitude, from 10 -6 to 10 2 (Ωcm) -1 . The highest σ(0), (=74.5 (Ωcm) -1 , for sample SFMO(N1)) is about 50 times lower than the metallic conductivity of an SFMO single crystal at T=0 [13].…”

Section: Inter-grain Tunnelling In Sr 2 Bb'omentioning

confidence: 99%

Inter-grain tunnelling in the half-metallic double-perovskites Sr₂BB'O₆(BB'= FeMo, FeRe, CrMo, CrW, CrRe)

Fisher

Genossar

Chashka

et al. 2014

EPJ Web of Conferences

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“…In the real world, such a large magnetization value has not been obtained for bulk Sr 2 FeMoO 6 up to date; instead smaller values bellow 3.7 µ B /f.u. have been reported (1,5,6). The origin of this difference with the theoretical magnetization can be found in the so-called anti-site B-cation disorder, implying that some Mo 5+ cations occupy the positions of Fe 3+ cations, and viceversa.…”

mentioning

confidence: 99%

“…The case of the half-metallic ferromagnet (ferrimagnet) Sr 2 FeMoO 6 is paradigmatic; with a Curie temperature above room temperature (T C = 415 K), it can be considered as a serious alternative to manganese perovskites for practical applications (1)(2)(3)(4)(5).…”

Section: Introductionmentioning

confidence: 99%

Origin of neutron magnetic scattering in antisite-disorderedSr2FeMoO6double perovskites

et al. 2002

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"ordered" sample with ∼70% of cationic ordering and a nominally "disordered" sample with ∼18% of cationic ordering) have been examined by magnetic measurements and neutron powder diffraction (NPD) techniques in the 15-500K temperature range. Our main finding is that the "disordered" sample exhibits a strong magnetic scattering (noticeable even at 500K), comparable to that displayed by the "ordered" one below T C = 415 K. For the "disordered" sample, the magnetic scattering exhibited on low angle Bragg positions, is not to be ascribed to a (non-existent) ferrimagnetic ordering: our results suggest that it originates upon naturally-occurring groups of Fe cations in which strong antiferromagnetic (AFM) Fe-O-Fe superexchange interactions are promoted, similar to those existing in the LaFeO 3 perovskite. These Fe groups are not magnetically isolated, but coupled by virtue of Fe-O-Mo AFM interactions, which maintain the longrange coherence of this AFM structure. Susceptibility measurements confirm the presence of AFM interactions below 770 K. * Corresponding author. Electronic mail: ja.alonso@icmm.csic.es IntroductionSome of the oxides of the double perovskites family A 2 B'B''O 6 (A= alkali-earth; B', B''= heterovalent transition metals) have been recently described to exhibit ferromagnetism and half-metallicity with a high spin polarization at the Fermi level, making them promising candidates as materials suitable for spin devices. The case of the half-metallic ferromagnet (ferrimagnet) Sr 2 FeMoO 6 is paradigmatic; with a Curie temperature above room temperature (T C = 415 K), it can be considered as a serious alternative to manganese perovskites for practical applications (1-5).The ideal structure of Sr 2 FeMoO 6 can be viewed as a regular arrangement of cornersharing FeO 6 and MoO 6 octahedra, alternating along the three directions of the crystal, with the voluminous Sr cations occupying the voids in between the octahedra. In a simple picture, the ferrimagnetic structure can be described as an ordered array of parallel Fe 3+ (S=5/2) magnetic moments, antiferromagnetically coupled with Mo 5+ (S=1/2) spins. In this ideal model, the saturation magnetization, at low temperature, would be of 4 µ B per formula unit (f.u.). In the real world, such a large magnetization value has not been obtained for bulk Sr 2 FeMoO 6 up to date; instead smaller values bellow 3.7 µ B /f.u. have been reported (1,5,6). The origin of this difference with the theoretical magnetization can be found in the so-called anti-site B-cation disorder, implying that some Mo 5+ cations occupy the positions of Fe 3+ cations, and viceversa.The problem of the order-disorder of B cations in double perovskites A 2 B'B''O 6 is a well-known one, and it has been previously addressed (7,8). If the charge difference between B' and B'' is greater than two, complete ordering of these cations is found, for instance in perovskites of the type A 2 B 2+ B 6+ O 6 and A 2 B + B 7+ O6. For them, a perfect rock-salt like structure is obtained for the B-cations sublattice...

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“…The revived interest on the double perovskites has its origin in the large tunneling magneto-resistance discovered in Sr 2 FeMoO 6 and Sr 2 FeReO 6 , 1,2 although it has already been known since 1960's that Sr 2 FeMoO 6 is a ferrimagnetic (or ferromagnetic) metal with a quite high ferrimagnetic transition temperature (T C ) of 420 K. 3 Several band-structure calculations and optical or electron-spectroscopic studies have confirmed that those iron-based compounds generally have the half-metallic density of states (DOS) at the Fermi level (E F ). 1,4,5,6,7,8,9 Ferrimagnetism accompanied by metallic conductivity and the half-metallic density of states (DOS) naturally reminds us of the colossal magnetoresistive manganates and the double exchange (DE) mechanism. Indeed, several authors have pointed out that DE can explain the electronic properties of Sr 2 FeMoO 6 , 8,9,10,11 while others have proposed a new mechanism of ferrimagnetic metal.…”

Section: Introductionmentioning

confidence: 99%

Unusual electron-doping effects inSr2−xLaxFeMoO6
Saitoh
¹
,
Nakatake
²
,
Nakajima
³

et al. 2005
Phys. Rev. B
19
2
13
0
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We have investigated the electronic structure of electron-doped Sr2−xLaxFeMoO6 (x=0.0 and 0.2) by photoemission spectroscopy and band-structure calculations within the local-density approximation+U (LDA+U ) scheme. A characteristic double-peak feature near the Fermi level (EF) has been observed in the valence-band photoemission spectra of both x=0.0 and 0.2 samples. A photon-energy dependence of the spectra in the Mo 4d Cooper minimum region compared with the band-structure calculations has shown that the first peak crossing EF consists of the (Fe+Mo) t 2g↓ states (feature A) and the second peak well below EF is dominated by the Fe e g↑ states (feature B). Upon La substitution, the feature A moves away from EF by ∼50 meV which is smaller than the prediction of our band theory, 112 meV. In addition, an intensity enhancement of both A and B has been observed, although B is not crossing EF. Those two facts are apparently incompatible with the simple rigid-band shift due to electron doping. We point out that such phenomena can be understood in terms of the strong Hund's rule energy stabilization in the 3d 5 configuration at the Fe sites in this compound. From an observed band-narrowing, we have also deduced a mass enhancement of ∼2.5 with respect to the band theory, in good agreement with a specific heat measurement.

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Magnetic and electronic properties of a single crystal of ordered double perovskiteSr2FeMoO6

Cited by 454 publications

References 12 publications

Inter-grain tunnelling in the half-metallic double-perovskites Sr₂BB'O₆(BB'= FeMo, FeRe, CrMo, CrW, CrRe)

Inter-grain tunnelling in the half-metallic double-perovskites Sr₂BB'O₆(BB'= FeMo, FeRe, CrMo, CrW, CrRe)

Origin of neutron magnetic scattering in antisite-disorderedSr2FeMoO6double perovskites

Unusual electron-doping effects inSr2−xLaxFeMoO6
Saitoh
¹
,
Nakatake
²
,
Nakajima
³

et al. 2005
Phys. Rev. B
19
2
13
0
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Magnetic and electronic properties of a single crystal of ordered double perovskiteSr2FeMoO6

Cited by 454 publications

References 12 publications

Inter-grain tunnelling in the half-metallic double-perovskites Sr2BB'O6(BB'= FeMo, FeRe, CrMo, CrW, CrRe)

Inter-grain tunnelling in the half-metallic double-perovskites Sr2BB'O6(BB'= FeMo, FeRe, CrMo, CrW, CrRe)

Origin of neutron magnetic scattering in antisite-disorderedSr2FeMoO6double perovskites

Unusual electron-doping effects inSr2−xLaxFeMoO6Saitoh1, Nakatake2, Nakajima3 et al. 2005Phys. Rev. B192130View full textAdd to dashboardCite

Contact Info

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Inter-grain tunnelling in the half-metallic double-perovskites Sr₂BB'O₆(BB'= FeMo, FeRe, CrMo, CrW, CrRe)

Inter-grain tunnelling in the half-metallic double-perovskites Sr₂BB'O₆(BB'= FeMo, FeRe, CrMo, CrW, CrRe)

Unusual electron-doping effects inSr2−xLaxFeMoO6
Saitoh
¹
,
Nakatake
²
,
Nakajima
³

et al. 2005
Phys. Rev. B
19
2
13
0
View full text Add to dashboard Cite