The ac-magnetic susceptibility and dielectric response of complex spin ordering processes in Mn3O4

Thota, Subhash; Singh, Kiran; Nayak, Sisir Kumar; Simon, Ch.; Kumar, Jitendra; Prellier, W.

doi:10.1063/1.4895054

Cited by 16 publications

(10 citation statements)

References 41 publications

(95 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Substitution of non-magnetic elements (dilution) inside these oxides at tetrahedral (A) or octahedral (B) sites often induces disorder or lattice distortions. Such issues may generate new pathways of magnetic interactions leading to some complex ferrimagnetic ordering with altered ground state [11][12][13][14][15][16][17][18] and brings about some interesting magnetic phenomena like reentrant spin-glass characteristics, magnetic frustration and bipolar exchange bias [19][20][21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Neutron diffraction study of the inverse spinels Co2TiO4 and Co2SnO4

et al. 2017

View full text Add to dashboard Cite

We report a detailed single-crystal and powder neutron diffraction study of Co2TiO4 and Co2SnO4 between the temperatures 1.6 K and 80 K to probe their spin structures in the ground state. For both compounds the strongest magnetic intensity was observed for the (111)M reflection due to ferrimagnetic ordering, which sets in below TN = 48.6 K and 41 K for Co2TiO4 and Co2SnO4, respectively. An additional low intensity magnetic reflection (200)M was noticed in Co2TiO4 due to the presence of an additional weak antiferromagnetic component. Interestingly, from both the powder and the single-crystal neutron data of Co2TiO4 we noticed a significant broadening of the magnetic (111)M reflection, possibly results from the disordered character of the Ti and Co atoms on the B site. Practically, the same peak broadening was found for the neutron powder data of Co2SnO4. On the other hand, from our single-crystal neutron diffraction data of Co2TiO4 we found a spontaneous increase of particular nuclear Bragg reflections below the magnetic ordering temperature. Our data analysis showed that this unusual effect can be ascribed to the presence of anisotropic extinction, which is associated to a change of the mosaicity of the crystal. In this case it can be expected that competing Jahn-Teller effects act along different crystallographic axes can induce anisotropic local strain. In fact, for both ions Ti 3+ and Co 3+ the 2tg levels split into a lower dxy level and yields a higher two-fold degenerate dxz/dyz level. As a consequence, one can expect a tetragonal distortion in Co2TiO4 with c/a < 1, which could not significantly detected in the present work.

show abstract

Section: Introductionmentioning

confidence: 99%

Neutron diffraction study of the inverse spinels Co2TiO4 and Co2SnO4

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The physical and chemical properties of first‐row binary transition‐metal oxides (TMOs) and their alloys are well studied in the literature because of their potential applications in Li‐ion batteries, catalysis, transformer cores, sensors and ultrahigh‐density magnetic recording media . TMOs with spinel crystal structure (i.e., AB

_{2} O_{4}

‐type) occupy a unique place in the field of material science because of their interesting physics, resulting from a variety of the distribution of magnetic cations between the tetrahedral A‐sites and octahedral B‐sites . Among such spinels cobalt oxide

{Co}_{3} O_{4}

and its solid solutions under reduced dimension and bulk grain size have received much attention recently due to their unique photocatalytic properties, heterogeneous catalytic activity for NO

_{x}

reduction, carbon‐monoxide oxidation, and removal of volatile organic compounds (VOC) .…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic studies of Co₂TiO₄ and Co₃O₄ two‐phase composites

Nayak

Dasari

Joshi

et al. 2016

Physica Status Solidi (b)

View full text Add to dashboard Cite

In this article, we report a comparative analysis of various spectroscopic studies including low‐temperature (25thinmathspacenormalKthinmathspace≤T≤300normalK) Raman spectroscopy of cobalt‐orthotitanate (Co2TiO4) and tricobalt‐tetraoxide (Co3O4), and their solid solutions false(1−xfalse) Co3O4+x of Co2TiO4 (0≤x≤1 (100 wt.%)). For all the lower and intermediate compositions, five Raman‐active modes were recognized at 689, 618, 518, 480, and 195cm−1 that are associated with A1g, Eg, and 3F2g phonon symmetries. Conversely, pure Co2TiO4 exhibits a broad spectrum of width ∼93.3cm−1 without any signatures of F2g(3) mode. At low‐temperatures (down to 25 K) the A1g and F2g peaks of both Co2TiO4 and Co3O4 shift toward the high‐frequency side with anomalies across the ferrimagnetic Néel temperature (TN ∼48±5K) and antiferromagnetic Néel temperature (TN∼ 30 ± 10 K), respectively. All the investigated samples exhibit two distinct bands at 576cm−1 (B1) and 665cm−1 (B2) in the Fourier transform infrared spectra recorded at 300±10 K, associated with the vibrational stretching of the metal–oxygen bonds of length ∼195.8 pm (B–O) and ∼185.4 pm (A–O), respectively. The intensity of these sharp bands gradually decreases as the crystal structure transforms from normal‐spinel (a=8.07 Å) to inverse‐spinel structure (a=8.45 Å). The X‐ray photoelectron spectroscopy (XPS) studies revealed that the Ti was incorporated into the octahedral B‐sites of inverse‐spinel structure of Co2TiO4. Interestingly, the XPS spectra of Co2TiO4 provide evidence of the trivalent character of Ti instead of tetravalent cationic configuration together with a weak Co3+ character at the octahedral sites. These results are discussed in terms of the binding‐energy (BE) difference between the O‐1s and Ti‐2p3/2 (Δ[O–Ti‐2p3/2] = BE(O‐1s) −BE(Ti‐2p3/2false)) and the mean chemical bond length lfalse[italicTi−Ofalse]. The peculiarities of all these results in consonance with the crystal‐structure (bond angles and bond lengths) and electron‐spin‐resonance studies are discussed in detail.

show abstract

“…The X-ray diffraction patterns of the Mn 3 O 4 polycrystalline samples exhibit the single phase character as reported previously [18]. In order to further determine the chemical compositions and elemental maps, the EDX and energy dispersive X-ray analysis (EDXA) spectra measurements were carried out, as shown in Figure 1.…”

Section: Resultsmentioning

confidence: 61%

High-Temperature Dielectric Relaxation Behaviors in Mn3O4 Polycrystals

et al. 2019

View full text Add to dashboard Cite

High temperature dielectric relaxation behaviors of single phase Mn3O4 polycrystalline ceramics prepared by spark plasma sintering technology have been studied. Two dielectric relaxations were observed in the temperature range of 200 K–330 K and in the frequency range of 20 Hz–10 MHz. The lower temperature relaxation is a type of thermally activated relaxation process, which mainly results from the hopping of oxygen vacancies based on the activation energy analysis. There is another abnormal dielectric phenomenon that is different from the conventional thermally activated behavior and is related to a positive temperature coefficient of resistance (PTCR) effect in the temperature region. In line with the impedance analyses, we distinguished the contributions of grains and grain boundaries. A comparison of the frequency-dependent spectra of the imaginary impedance with imaginary electric modulus suggests that both the long range conduction and the localized conduction are responsible for the dielectric relaxations in the Mn3O4 polycrystalline samples.

show abstract

The ac-magnetic susceptibility and dielectric response of complex spin ordering processes in Mn3O4

Cited by 16 publications

References 41 publications

Neutron diffraction study of the inverse spinels Co2TiO4 and Co2SnO4

Neutron diffraction study of the inverse spinels Co2TiO4 and Co2SnO4

Spectroscopic studies of Co₂TiO₄ and Co₃O₄ two‐phase composites

High-Temperature Dielectric Relaxation Behaviors in Mn3O4 Polycrystals

Contact Info

Product

Resources

About

The ac-magnetic susceptibility and dielectric response of complex spin ordering processes in Mn3O4

Cited by 16 publications

References 41 publications

Neutron diffraction study of the inverse spinels Co2TiO4 and Co2SnO4

Neutron diffraction study of the inverse spinels Co2TiO4 and Co2SnO4

Spectroscopic studies of Co2TiO4 and Co3O4 two‐phase composites

High-Temperature Dielectric Relaxation Behaviors in Mn3O4 Polycrystals

Contact Info

Product

Resources

About

Spectroscopic studies of Co₂TiO₄ and Co₃O₄ two‐phase composites