Pressure-induced suppression of charge order and nanosecond valence dynamics in Fe<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>OBO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>3</mml:mn></mml:msub></mml:math>

Hearne, G. R.; Sibanda, W. N.; Carleschi, Emanuela; Pischedda, V.; Attfield, J. Paul

doi:10.1103/physrevb.86.195134

Cited by 12 publications

(18 citation statements)

References 23 publications

(43 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At present there are reports on only two homo-metallic (M ¼M′) warwickites: Fe 2 BO 4 [2][3][4][5][6] and Mn 2 BO 4 [4,[6][7][8], exhibiting both long-range magnetic order. Several studies have been done on different magnetic properties of heterometallic (M≠M′) warwickites with only one magnetic ion, MgTiBO 4 [9][10][11], MgCrBO 4 [12], MgFeBO 4 [12,13], NiScBO 4 [12], MnScBO 4 [12], MgVBO 4 [12,14].…”

Section: Introductionmentioning

confidence: 98%

Spin-glass behavior in single crystals of hetero-metallic magnetic warwickites MgFeBO4, Mg0.5Co0.5FeBO4, and CoFeBO4

Arauzo

Kazak

Ivanovа

et al. 2015

Journal of Magnetism and Magnetic Materials

View full text Add to dashboard Cite

a b s t r a c tMagnetic properties of heterometallic warwickites MgFeBO 4, Mg 0.5 Co 0.5 FeBO 4, and CoFeBO 4 are presented, highlighting the effect of Co substitution on the magnetic properties of these compounds. The analysis of magnetization and heat capacity data has shown that these compounds exhibit a spin-glass transition below T SG ¼10, 20 and 22 K, respectively. Using zero field ac susceptibility as entanglement witness we find that the low dimensional magnetic behavior above T SG show quantum entanglement behavior χ(Τ)∝T À α(Τ) up to T E E 130 K. The α parameters have been deduced as a function of temperature and Co content, indicating the existence of random singlet phase in this temperature region. Above T E the paramagnetism is interpreted in terms of non-entangled spins giving rise to Curie-Weiss paramagnetism. The different intra-and inter-ribbon exchange interaction pathways have been calculated within a simple indirect coupling model. It is determined that the triangular motifs in the warwickite structure, together with the competing interactions, induce frustration. The spin-glass character is explained in terms of the substitutional disorder of the Mg, Fe and Co atoms at the two available crystallographic sites, and the frustration induced by the competing interactions. The Co substitution induces uniaxial anisotropy, increases the absolute magnetization and increases the spin-glass freezing temperature. The entanglement behavior is supported in the intermediate phase irrespective of the introduction of anisotropy by the Co substitution.

show abstract

Section: Introductionmentioning

confidence: 98%

Spin-glass behavior in single crystals of hetero-metallic magnetic warwickites MgFeBO4, Mg0.5Co0.5FeBO4, and CoFeBO4

Arauzo

Kazak

Ivanovа

et al. 2015

Journal of Magnetism and Magnetic Materials

View full text Add to dashboard Cite

show abstract

“…Only two homometallic warwickites, Fe 2 BO 4 and Mn 2 BO 4 , have been reliably characterized so far. Both are mixed‐valent compounds and demonstrate magnetic, structural, and charge ordering transitions . In addition, the relationship of the electronic and crystal structures in two phases of the Fe 2 BO 4 has been assessed, and compared to the V‐doped sample where no charge ordering or structural phase transitions take place in a theoretical work .…”

Section: Introductionmentioning

confidence: 99%

Crystal and local atomic structure of MgFeBO₄ , Mg_0.5 Co_0.5 FeBO₄ and CoFeBO₄ : Effects of Co substitution

Kazak

Платунов

Knyazev

et al. 2015

Phys. Status Solidi B

View full text Add to dashboard Cite

Single‐crystalline MgFeBO4, Mg0.5Co0.5FeBO4, and CoFeBO4 have been grown by the flux method. The samples have been characterized by X‐ray spectral analysis, X‐ray diffraction, and X‐ray absorption spectroscopy. The X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) spectra have been measured at the Fe and Co K‐edges over a wide temperature range (6.5–300 K). The composition, the charge state, and local environment of both Fe and Co atoms have been determined. The effects of Co substitution for Mg on the local structural distortions have been revealed experimentally and the MO bond anisotropy has been found.

show abstract

“…Evidently strong electron correlations (U /t 1) and associated insulating behavior persist to extreme conditions, likely as high as 50-60 GPa. Prior 57 Fe ME studies have shown drastic disruption to the CO at ß16 GPa [18], so electrical-transport measurements suggest that this CO instability is not associated with metallization.…”

Section: Experimental Details and Resultsmentioning

confidence: 93%

“…1(a) [19]. Powdered sample from the same batch of the previous 57 Fe Mössbauer effect (ME) study was loaded into the insulated gasket hole [6,18]. A ruby ball for pressure determination was embedded in the sample powder, between the voltage leads [20].…”

Section: Experimental Details and Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Wigner-Mott insulator-to-insulator transition at pressure in charge-ordered Fe2OBO3

et al. 2014

Self Cite

View full text Add to dashboard Cite

Magnetic-electronic studies of mixed-valence Fe 2 OBO 3 have shown that ionic charge order (CO) is disrupted at ß16 GPa. The pertinent minority-spin carrier exhibits persistent intersite electron exchange Fe 2+ ⇔ Fe 3+ to well beyond this pressure. Temperature-dependent electrical transport measurements over an extended pressure range presented here demonstrate that the electronic structure remains gapped to well beyond 16 GPa. Extrapolation of data to higher pressure suggests that metallization will only prevail at P > 50 GPa. Both the persistent gapped electronic state across the CO instability and signature of carrier confinement to Fe-Fe dimers in the Fe 2+ ⇔ Fe 3+ electron exchange are rationalized as crossover from a Wigner crystal (site centered) insulator to a dimer Mott (bond centered type) insulator-"Wigner-Mott transition" at ß16 GPa. The dimer insulating state is a consequence of modulation of the relevant hopping parameter t in quasi-low-dimensional features in the structure (ribbons and chains). Complementary structural studies suggest that the a axis is appreciably more compressible than other crystallographic directions of the original monoclinic unit cell. Therefore, such a modulation in t may arise from Peierls type distortions along the a axis or else stems from intrinsic modulation in the c axis direction of the unit cell. This is aided by a monoclinic (P 2 1 /c) → orthorhombic (Pmcn) structural adjustment that is concurrent across the electronic transition. Pressure tuning of relative values of on-site U /t and intersite V /t Coulomb interaction parameters of the quasi-low-dimensional features evolve the system from site-centered to dimer-centered electron localization.

show abstract

Pressure-induced suppression of charge order and nanosecond valence dynamics in Fe2OBO3

Cited by 12 publications

References 23 publications

Spin-glass behavior in single crystals of hetero-metallic magnetic warwickites MgFeBO4, Mg0.5Co0.5FeBO4, and CoFeBO4

Spin-glass behavior in single crystals of hetero-metallic magnetic warwickites MgFeBO4, Mg0.5Co0.5FeBO4, and CoFeBO4

Crystal and local atomic structure of MgFeBO₄ , Mg_0.5 Co_0.5 FeBO₄ and CoFeBO₄ : Effects of Co substitution

Wigner-Mott insulator-to-insulator transition at pressure in charge-ordered Fe2OBO3

Contact Info

Product

Resources

About

Pressure-induced suppression of charge order and nanosecond valence dynamics in Fe2OBO3

Cited by 12 publications

References 23 publications

Spin-glass behavior in single crystals of hetero-metallic magnetic warwickites MgFeBO4, Mg0.5Co0.5FeBO4, and CoFeBO4

Spin-glass behavior in single crystals of hetero-metallic magnetic warwickites MgFeBO4, Mg0.5Co0.5FeBO4, and CoFeBO4

Crystal and local atomic structure of MgFeBO4 , Mg0.5 Co0.5 FeBO4 and CoFeBO4 : Effects of Co substitution

Wigner-Mott insulator-to-insulator transition at pressure in charge-ordered Fe2OBO3

Contact Info

Product

Resources

About

Crystal and local atomic structure of MgFeBO₄ , Mg_0.5 Co_0.5 FeBO₄ and CoFeBO₄ : Effects of Co substitution