Electron doping effect on structural and magnetic phase transitions in Sr2−xNdxFeMoO6 double perovskites

Azad, Abul K.; Eriksson, Sten; Khan, Abdullah; Eriksson, Annika K.; Tseggai, M.

doi:10.1016/j.jssc.2006.01.043

Cited by 35 publications

(23 citation statements)

References 32 publications

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“…Furthermore, we attempted to reduce the ASD by using a wet chemistry procedure that yields a homogeneous cationic distribution at atomic levels, as demonstrated for the undoped Sr 2 FeMoO 6 perovskite. [13] Azad et al have reported [14] the structural and magnetic properties of the Nd-doped series up to x = 0.4. The present study extends this series up to x = 0.6 and describes a non-monotonic behaviour of T c .…”

Section: Introductionmentioning

confidence: 99%

The Magnetotransport Properties and a Neutron Diffraction Study of Sr_2–xNd_xFeMoO₆ Double Perovskites

et al. 2009

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New electron‐doped derivatives of the Sr2FeMoO6 double perovskite have been studied. We report on the synthesis of the Sr2–xNdxFeMoO6 (x = 0, 0.2, 0.4 and 0.6) perovskite series by a wet chemistry procedure and its characterization. The evolution of the crystal and magnetic structure has been analyzed from neutron powder diffraction data. The partial replacement of Sr2+ cations by higher valence Nd3+ cations induces an injection of electrons into the Fe/Mo sublattice. A bond‐valence study demonstrates that this electron‐injection preferentially affects the Mo orbitals. This substitution leads to a distortion of the structure from tetragonal (I4/m) to monoclinic (P21/n) at room temperature for x ≥ 0.4 and an increase of the disorder between Fe and Mo cations. This effect has severe consequences for the magnetic properties, notably a reduction of the saturation magnetization and a non‐monotonic behavior of the Curie temperature. Magnetotransport measurements show a significant increment of the magnetoresistance at low temperature for high values of x. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Introductionmentioning

confidence: 99%

The Magnetotransport Properties and a Neutron Diffraction Study of Sr_2–xNd_xFeMoO₆ Double Perovskites

et al. 2009

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“…As discussed in the introduction, a considerable high T C of SFMO origins from the strong magnetic interactions via a double-exchange-like mechanism. Ferromagnetic coupling strengthen is proposed to be mediated by n. Actually, T C indeed can be signicantly improved by electron doped FeMo-based double perovskites, 16,[18][19][20][21][22]45,46 and it is noted that the theoretical n of such subjects investigated are greater than 1. And T C values have a monotonously positive correlation with n due to the electron band lling effect.…”

Section: Resultsmentioning

confidence: 96%

Effect of the itinerant electron density on the magnetization and Curie temperature of Sr₂FeMoO₆ ceramics

et al. 2018

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The itinerant electron density (n) near the Fermi level has a close correlation with the physical properties of Sr 2 FeMoO 6 . Two series of single-phase Sr (2Ày) Na y FeMoO 6 (y ¼ 0.1, 0.2, 0.3) and Sr (2Ày) Na y Fe (1Àx) Mo (1+x) O 6 (y ¼ 2x; y ¼ 0.1, 0.2, 0.3) ceramics were specially designed and the itinerant electron density (n) of them can be artificially controlled to be: n ¼ 1 À y and n ¼ 1 À y + 3x ¼ 1 + 0.5y, respectively. The corresponding crystal structure, magnetization and the ferromagnetic Curie temperature (T C ) of two subjects were investigated systematically. The X-ray diffraction analysis indicates that Sr (2Ày) Na y behavior confirms that it is the Fe/Mo ASD not n that dominantly determines the magnetization properties. Interestingly, approximately when n # 0.9, T C of Sr (2Ày) Na y FeMoO 6 (y ¼ 0.1, 0.2, 0.3) exhibits an overall increase with decreasing n, which is contrary to the T C response in electron-doped SFMO.Such abnormal T C is supposed to relate with the ratio variation of n(Mo)/n(Fe). Moreover, when n $ 1, T C of Sr (2Ày) Na y Fe (1Àx) Mo (1+x) O 6 (y ¼ 2x; y ¼ 0.3) exhibits a considerable rise of about 75 K over that of Sr (2Ày) Na y Fe (1Àx) Mo (1+x) O 6 (y ¼ 2x; y ¼ 0.1), resulting from improved n caused by introducing excess Mo into Sr (2Ày) Na y FeMoO 6 . Maybe, our work can provide an effective strategy to artificially control n and ferromagnetic T C accordingly, and provoke further investigation on the FeMo-baseddouble perovskites.

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“…These effects are observed and investigated by many groups. 4,6,11,13 The MR behavior of the samples at 80 and 300 K are shown in Figs. 3͑a͒ and 3͑b͒.…”

Section: Resultsmentioning

confidence: 99%

“…Electron doping through trivalent substitution at divalent "A" site has been proved to be one of the best way to increase the Curie temperature in these compounds. [3][4][5][6][7] Trivalent doping adds one electron to these double perovskite systems which preferably occupy Mo 4d↓ site. Further the calculations predicted that the down spin band ͑hybridized Fe 3d, O 2p, and Mo 4d͒ in these systems crosses the Fermi level.…”

Section: Introductionmentioning

confidence: 99%

“…Also a decrease in Mo valence state with electron doping further reduces charge difference between Fe and Mo site, and leads to increase in disorder defects in the system ultimately reducing the spin polarization of the system. 6,9,10 Although, the antisite disorder defect values can be controlled thermodynamically in electron doped systems, 5 however, the loss of spin polarization cannot be prevented. In summary, the most commonly observed results with electron doping in these systems are the increase in Curie temperature, decrease in saturation magnetization, reduced spin polarization, and finally reduced magnetoresistive response of the system.…”

Section: Introductionmentioning

confidence: 99%

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Increased low field magnetoresistance in electron doped system Sr0.4Ba1.6−xLaxFeMoO6

Pandey

Verma

Bhalla

et al. 2010

Journal of Applied Physics

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Magnetotransport properties of electron doped polycrystalline system Sr0.4Ba1.6−xLaxFeMoO6 are presented in this paper. We have observed increased low field magnetoresistance values with significant Curie temperature increase in the electron doped system Sr0.4Ba1.6−xLaxFeMoO6. The low field magnetoresistance value (at 1000 Oe) in 20% La3+ doped sample is observed to be 2.17% at 300 K. At 0.64 T and 80 K, the magnetoresistance change measured in this sample is 21.4%. This sample also showed 50 K increase in Curie temperature over the pristine sample. The increased low field magnetoresistance values are associated with modified grain boundary barriers of the system. The results confirm the fact that the modification of grain boundary barriers has enough potential to possess high low field magnetoresistance values even in the systems with lower spin polarization values. The role of grain to grain connectivity is observed to be dominantly determining the low field magnetoresistance values in grain to grain tunnel type magnetoresistance.

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Electron doping effect on structural and magnetic phase transitions in Sr2−xNdxFeMoO6 double perovskites

Cited by 35 publications

References 32 publications

The Magnetotransport Properties and a Neutron Diffraction Study of Sr_2–xNd_xFeMoO₆ Double Perovskites

The Magnetotransport Properties and a Neutron Diffraction Study of Sr_2–xNd_xFeMoO₆ Double Perovskites

Effect of the itinerant electron density on the magnetization and Curie temperature of Sr₂FeMoO₆ ceramics

Increased low field magnetoresistance in electron doped system Sr0.4Ba1.6−xLaxFeMoO6

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Electron doping effect on structural and magnetic phase transitions in Sr2−xNdxFeMoO6 double perovskites

Cited by 35 publications

References 32 publications

The Magnetotransport Properties and a Neutron Diffraction Study of Sr2–xNdxFeMoO6 Double Perovskites

The Magnetotransport Properties and a Neutron Diffraction Study of Sr2–xNdxFeMoO6 Double Perovskites

Effect of the itinerant electron density on the magnetization and Curie temperature of Sr2FeMoO6 ceramics

Increased low field magnetoresistance in electron doped system Sr0.4Ba1.6−xLaxFeMoO6

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The Magnetotransport Properties and a Neutron Diffraction Study of Sr_2–xNd_xFeMoO₆ Double Perovskites

The Magnetotransport Properties and a Neutron Diffraction Study of Sr_2–xNd_xFeMoO₆ Double Perovskites

Effect of the itinerant electron density on the magnetization and Curie temperature of Sr₂FeMoO₆ ceramics