Room-Temperature Ferromagnetism in Reduced Rutile TiO<sub>2−δ</sub> Nanoparticles

Parras, M.; Varela, Áurea; Cortés‐Gil, Raquel; Boulahya, Khalid; Hernando, A.; Calbet, José María González

doi:10.1021/jz401115q

Cited by 56 publications

(40 citation statements)

References 29 publications

(56 reference statements)

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“…The modulated AFM order transformed to a collinear FM order in a magnetic field above 21 kOe at 5 K. For example, the difference between the zero-field and non-zero-field ND profiles clearly revealed the presence of FM order (Figure 6a), which gradually developed with increasing magnetic field (Figure 6b). Figure 6c shows the applied magnetic field dependence of the magnetic peak intensity at 2θ = 30, which indicates The magnetic moments in the FM state at 5 K were estimated to be 2.13 (8) (Figure 3b), although the ND analysis yields approximately 3 µB/f.u. in total.…”

Section: Resultsmentioning

confidence: 98%

Ba2NiOsO6 : A Dirac-Mott insulator with ferromagnetism near 100 K

et al. 2016

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The ferromagnetic semiconductor Ba2NiOsO6 (Tmag ~100 K) was synthesized at 6 GPa and 1500 C. It crystallizes into a double perovskite structure a = 8.0428 plays an essential role in opening the charge gap. The magnetic state was investigated by density functional theory calculations and powder neutron diffraction. The latter revealed a collinear ferromagnetic order in a >21 kOe magnetic field at 5 K. The ferromagnetic gapped state is fundamentally different from that of known dilute magnetic semiconductors such as (Ga,Mn)As and (Cd,Mn)Te (Tmag < 180 K), the spin-gapless semiconductor Mn2CoAl (Tmag ~720 K), and the ferromagnetic insulators EuO (Tmag ~70 K) and Bi3Cr3O11 (Tmag ~220 K). It is also qualitatively different from known ferrimagnetic insulator/semiconductors, which are characterized by an antiparallel spin arrangement. Our finding of the ferromagnetic semiconductivity of Ba2NiOsO6 should increase interest in the platinum group oxides, because this new class of materials should be useful in the development of spintronic, quantum magnetic, and related devices.3

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Section: Resultsmentioning

confidence: 98%

Ba2NiOsO6 : A Dirac-Mott insulator with ferromagnetism near 100 K

et al. 2016

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“…This behavior is also found in the temperature dependence of the high field magnetization (applied magnetic field, µ 0 H = 6 T). The coexistence of both contributions has been reported in other doped and oxygen defective nanostructures [23], where the nearly independent magnetization is ascribed to the induced ferromagnetic component in the semiconductor. Finally, it should be outlined that all the samples display a certain splitting in the Zero Field Cool (ZFC)-Field Cool (FC) magnetization curves.…”

Section: Resultsmentioning

confidence: 65%

Magnetic Properties of N- and (Cr, N)-Doped TiO<sub>2</sub> Nanoparticles

Larumbe

Gomez-Polo

2015

IEEE Trans. Magn.

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The effect of N and Cr doping on the magnetic properties of TiO 2 nanoparticles is analyzed in the present work. N and (Cr,N) doped TiO 2 nanoparticles were synthesized by sol-gel method using Titanium Tetraisopropoxide (TTIP) as metallic precursor, and urea and chromium nitrate as N and Cr doping precursors, respectively. The calcined nanoparticles were analyzed through X-ray diffraction and Rietveld refinement. The samples display anatase structure with mean grain sizes around 5 nm. A distortion of the anatase cell is detected (increase and decrease of a and c lattice parameters, respectively) with respect to the reported anatase bulk values. The room temperature hysteresis loops of the samples display the coexistence of paramagnetic and ferromagnetic contributions. An enhancement in the ferromagnetic component is observed upon Cr and N co-doping. The analysis of the temperature dependence of the magnetization confirms the coexistence of both para and ferromagnetic contributions. Although the existence of a secondary phase cannot be completely excluded in the (Cr,N)-doped sample with the highest nitrogen content, the results confirms the achievement of intrinsic room temperature ferromagnetism in these doped semiconductor nanostructures.

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“…The main disadvantages of this strategy are crystal growth and agglomeration caused by the high temperatures required for reduction of the stable Ti 4+ to Ti 3+ . One of our previous articles evidenced that average particle size can be kept below 50 nm, particles ranging 5–10 nm can even be found, when a very small amount of material is reduced under strict control in a Cahn electrobalance. It allowed us to discuss the magnetic properties, room temperature ferromagnetism, of nanostructured Magnéli phases which were attributed to the presence of anionic vacancies in a previous article, and we evidence that this peculiar behavior was actually caused by the presence of Ti 3+ in the CS planes.…”

Section: Synthesis and Propertiesmentioning

confidence: 99%

Modified Synthesis Strategies for the Stabilization of low n Ti_nO_2n–1 Magnéli Phases

Azor-Lafarga

Ruiz‐González

Parras

et al. 2018

The Chemical Record

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Titanium reduced oxides TiO occupy, since long time, a prominent place on the landscape of binary metal oxides because of their intriguing ability to form extended defects that affect both the formation of new superlattices and different electronic behaviours. Related to these features, a wide range of practical applications has been achieved. Moved by the conviction of the great potential of understanding the influence of the reactivity, compositional variations and size effects on their functional properties, the aim of this personal account is the optimization of a recently developed strategy for the stabilization of low n Ti O terms. In particular, we will focus on the Ti O composition as well as the incorporation of transition metals, like Mn, in order to deal with new reduced Magnéli phases.

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Room-Temperature Ferromagnetism in Reduced Rutile TiO_2−δ Nanoparticles

Cited by 56 publications

References 29 publications

Ba2NiOsO6 : A Dirac-Mott insulator with ferromagnetism near 100 K

Ba2NiOsO6 : A Dirac-Mott insulator with ferromagnetism near 100 K

Magnetic Properties of N- and (Cr, N)-Doped TiO<sub>2</sub> Nanoparticles

Modified Synthesis Strategies for the Stabilization of low n Ti_nO_2n–1 Magnéli Phases

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Room-Temperature Ferromagnetism in Reduced Rutile TiO2−δ Nanoparticles

Cited by 56 publications

References 29 publications

Ba2NiOsO6 : A Dirac-Mott insulator with ferromagnetism near 100 K

Ba2NiOsO6 : A Dirac-Mott insulator with ferromagnetism near 100 K

Magnetic Properties of N- and (Cr, N)-Doped TiO<sub>2</sub> Nanoparticles

Modified Synthesis Strategies for the Stabilization of low n TinO2n–1 Magnéli Phases

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Room-Temperature Ferromagnetism in Reduced Rutile TiO_2−δ Nanoparticles

Modified Synthesis Strategies for the Stabilization of low n Ti_nO_2n–1 Magnéli Phases