Ferromagnetic coupling strength and electron-doping effects in double perovskites

Fontcuberta, J.; Rubi, D.; Frontera, C.; García-Muñoz, J. L.; Wójcik, Marek J.; Jędryka, E.; Nadolski, S.; Izquierdo, M.; Ávila, J.; Asensio, M. C.

doi:10.1016/j.jmmm.2004.11.570

Cited by 8 publications

(3 citation statements)

References 24 publications

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“…9,11,14,15 The carrier density at the Fermi level has been proposed to have a close correlation with the T C of the double perovskite. [15][16][17][18][19][20][21] Actually, the ferromagnetic T C of A 2 FeMoO 6 (A: Ca/Ba/Sr) can indeed be signicantly enhanced by substituting the divalent A 2+ ions with the trivalent ions (such as La 3+ , Nd 3+ , Sm 3+ etc.). 15,17,19,[22][23][24][25][26][27] A substantial increase in the ferromagnetic T C is because of the increase in the carrier density caused by electron injection into the conduction band.…”

Section: Introductionmentioning

confidence: 99%

Combined effects of hole doping and off-stoichiometry on the structures, transport, and magnetic properties of Sr_(2−y)Na_yFe_(1−x)Mo_(1+x)O₆ (x = 0/5x = y; y = 0, 0.05, 0.1, 0.15, 0.2, and 0.3)

Wang

Zhang

2017

RSC Adv.

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Section: Introductionmentioning

confidence: 99%

Combined effects of hole doping and off-stoichiometry on the structures, transport, and magnetic properties of Sr_(2−y)Na_yFe_(1−x)Mo_(1+x)O₆ (x = 0/5x = y; y = 0, 0.05, 0.1, 0.15, 0.2, and 0.3)

Wang

Zhang

2017

RSC Adv.

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“…Strong antiferromagnetic correlation exists between the localized magnetic moments (Fe 3+ : 3d 5 ) and the delocalized electron (Mo 5+ : 4d 1 ) in a double-exchange-like type, the magnetic coupling induces a ferrimagnetic state with an ideal saturated magnetization (MS) of 4 per formula unit [2][3][4][5][6][7]. The strength of magnetic coupling in SFMO double perovskite is mainly controlled by the carrier density at the Fermi level, so it indicates that doping electrons in the conduction band is an effective way to enhance TC [8][9][10][11][12][13][14]. This point was confirmed by a substantial enhancement of TC more than 80 K in LaxSr(2-x)FeMoO6 [9]and (Ba0.8Sr0.2)2-xLaxFeMoO6 materials [15].…”

Section: Introductionmentioning

confidence: 99%

Effects of organic material on magnetoresistance in electron-doped double perovskite

Liu

Zhang

et al. 2021

J Mater Sci: Mater Electron

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The Curie temperature of electron-doped Sr2FeMoO6 can be optimized significantly due to the band-filling effect, but accompanying an almost absent low-field magnetoresistance (LFMR), which is unfavorable to applications in the magnetoresistive devices operated at room-temperature. Our previous works confirmed that, a remarkable enhanced LFMR was observed in Sr2FeMoO6 by modifying the grain boundary with insulating organic small molecules (glycerin, CH2OHCHOHCH2OH). However, in this work, modifying the grain boundary strength of the La0.5Sr1.5FeMoO6 with the insulating organic macromolecules (oleic acid, CH3(CH2)7CH=CH(CH2)7COOH) or small molecules (glycerin), both of them have negligible functions on the magnetoresistance behavior in La0.5Sr1.5FeMoO6. Contrary to the glycerin-modified Sr2FeMoO6, Sr2FeMoO6/oleic acid composites don't exhibit an obviously increased magnetoresistance property. Based on the above experimental results and the related works, it is proposed that, maintaining high spin polarization of the carriers at the Fermi level and improving the tunneling process across the grain boundary by using the suitable organic materials are decisive factors for optimizing the magnetoresistance behavior in the similar electron-doped double perovskites.

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“…The electronic properties of the Fe-Mo and Fe-Re double perovskites have been studied theoretically and experimentally by several authors [25][26][27][28][29][30][31][32][33][34]. The calculations of the density of states (DOS) reveal a gap in the majority spin band at the Fermi level.…”

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Local Magnetic and Electronic Properties of the A2FeM'O6 (A = Ba, Sr, Ca, M' = Mo, Re) Double Perovskites

et al. 2007

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The results of a combined NMR, X-ray absorption spectroscopy and X-ray magnetic circular dichroism study of the AA FeMoO6 and AA FeReO6 double perovskites are presented. They revealed a dependence of electronic and magnetic properties, including a d-electron transfer between Fe and Mo sites, on the structural tolerance factor. The maximum value of the 4d Mo electron occupation and the corresponding Mo moment is obtained for the tolerance factor of unity. This corresponds to the maximum strength of the magnetic interaction and, respectively, to the Curie temperature. The dominant T 5/2 type temperature dependence of the Mo hyperfine field reveals the half-metallicity of the AA FeMoO 6 compounds. Antisite defects and antiphase boundaries have been identified in NMR measurements and the strength of their magnetic coupling have been determined. A considerable orbital contribution to the Re and Fe magnetic moments were found in the NMR and X-ray magnetic circular dichroism measurements on the AA FeReO6 compounds. Its magnitude decreases with increasing structural tolerance factor and is correlated with their magnetic anisotropy. IntroductionDouble perovskites (DP) of a general formula A 2 MM O 6 , where A is an alkaline earth, and M and M are 3d, 4d, and/or 5d transition metals belong to a very broad family of oxide compounds crystallising in the perovskite structure. They exhibit intriguing magnetic and electronic properties including half metallicity, a considerable low field magnetoresistance (LFMR) and a variety of magnetic structures, see review paper [1]. Magnetic and electronic properties are closely interrelated, due to the same (d) character of the "magnetic" and "conduction" electrons. Exchange interactions can occur between ions of the same element, as e.g. in manganese perovskites, as well as between ions of different elements, as e.g. in double perovskites. The interplay of lattice, charge, and spin degrees of freedom causes a variety of electronic and magnetic properties ranging from a metallic ferro-or ferrimagnetism to antiferromagnetic or paramagnetic insulating behaviour. This also brings about the magnetoresistive properties of the compounds.The interplay between magnetic and electronic transport properties in these systems can be controlled by substitution of alkaline earths (e.g. Ba, Sr, Ca) or lanthanides (e.g. La, Pr, Nd) in the A-site, as well as by the substitution of transition metals (e.g. Fe, Cr, Mn, Mo, Rh, Ru, W, Re). Among the double perovskites, the Fe-Mo and Fe-Re compounds, which are the subject of the study presented in this paper, have recently attracted a great deal of interest among the researchers. Their relatively high magnetic ordering temperature (in most cases higher than the room temperature) compared to that of manganese perovskites, and a significant LFMR make them especially interesting for applications, e.g. in magnetoelectronics or spintronics. The LFMR is explained in terms of intergranular tunneling MR (ITMR), and is related to the half-metallic nature of the ground...

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Ferromagnetic coupling strength and electron-doping effects in double perovskites

Cited by 8 publications

References 24 publications

Combined effects of hole doping and off-stoichiometry on the structures, transport, and magnetic properties of Sr_(2−y)Na_yFe_(1−x)Mo_(1+x)O₆ (x = 0/5x = y; y = 0, 0.05, 0.1, 0.15, 0.2, and 0.3)

Combined effects of hole doping and off-stoichiometry on the structures, transport, and magnetic properties of Sr_(2−y)Na_yFe_(1−x)Mo_(1+x)O₆ (x = 0/5x = y; y = 0, 0.05, 0.1, 0.15, 0.2, and 0.3)

Effects of organic material on magnetoresistance in electron-doped double perovskite

Local Magnetic and Electronic Properties of the A2FeM'O6 (A = Ba, Sr, Ca, M' = Mo, Re) Double Perovskites

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Ferromagnetic coupling strength and electron-doping effects in double perovskites

Cited by 8 publications

References 24 publications

Combined effects of hole doping and off-stoichiometry on the structures, transport, and magnetic properties of Sr(2−y)NayFe(1−x)Mo(1+x)O6 (x = 0/5x = y; y = 0, 0.05, 0.1, 0.15, 0.2, and 0.3)

Combined effects of hole doping and off-stoichiometry on the structures, transport, and magnetic properties of Sr(2−y)NayFe(1−x)Mo(1+x)O6 (x = 0/5x = y; y = 0, 0.05, 0.1, 0.15, 0.2, and 0.3)

Effects of organic material on magnetoresistance in electron-doped double perovskite

Local Magnetic and Electronic Properties of the A2FeM'O6 (A = Ba, Sr, Ca, M' = Mo, Re) Double Perovskites

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Combined effects of hole doping and off-stoichiometry on the structures, transport, and magnetic properties of Sr_(2−y)Na_yFe_(1−x)Mo_(1+x)O₆ (x = 0/5x = y; y = 0, 0.05, 0.1, 0.15, 0.2, and 0.3)

Combined effects of hole doping and off-stoichiometry on the structures, transport, and magnetic properties of Sr_(2−y)Na_yFe_(1−x)Mo_(1+x)O₆ (x = 0/5x = y; y = 0, 0.05, 0.1, 0.15, 0.2, and 0.3)