A transmission electron microscopy study of lattice defects in Mn<sub>3</sub>O<sub>4</sub> hausmannite

Couderc, Jean-Jacques; Fritsch, Sophie; Brieu, M.; Vanderschaeve, G.; Fagot, M.; Rousset, A.

doi:10.1080/01418639408240274

Cited by 18 publications

(20 citation statements)

References 22 publications

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“…Similar microstructural observations have been reported for quenched Mn 3 O 4 [24,25] and in those works the laths have been interpreted as incoherent boundaries of type {110} and the internal twinning of each lath can be ascribed to coherent boundaries of the same type because of accomodation twinning according to the cubic to tetragonal phase transition. Similar microstructural observations have been reported for quenched Mn 3 O 4 [24,25] and in those works the laths have been interpreted as incoherent boundaries of type {110} and the internal twinning of each lath can be ascribed to coherent boundaries of the same type because of accomodation twinning according to the cubic to tetragonal phase transition.…”

Section: Discussionsupporting

confidence: 84%

Microstructure and Electrical Properties of Mn-Ni-In Spinels

Metzmacher

Groen

Reaaney

2000

phys. stat. sol. (a)

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Microstructural investigations of negative temperature coefficient (NTC) ceramics in the Mn±Ni±In±O system have been performed using X-ray diffraction (XRD), scanning (SEM) and transmission electron microscopy (TEM). The electrical properties have been characterized by measurements of resistance, activation energy and aging. The replacement of Mn by In in Mn 2.9± ±x Ni x In 0.1 O 4 (x 0:50À0:66) leads to higher resistivities and thermal constants, both decreasing with increasing Ni content, and minimum aging of 0.1% for x 0:58. Microstructural changes deduced from the a/c ratio and caused by aging are observable for Mn 2.32 Ni 0.58 In 0.1 O 4 which is nearest to the tetragonal/cubic phase boundary. It is concluded that the Mn 3 concentration on octahedral sites increases due to aging. The domain configuration changes with increasing Ni content: samples with low Ni content reveal domain laths ($100 nm width) with internal twinning (<10 nm), samples near to the boundary exhibit finer scaled (5±10 nm), weakly curved domains without twinning and for high Ni contents a slightly increased domain width of 5±15 nm is observed. With the exception of x 0:58, all aged samples show the same microstructure as the corresponding non-aged ones, whereas aged Mn 2.32 Ni 0.58 In 0.1 O 4 is more comparable with Mn 2.40 Ni 0.50 In 0.1 O 4 . Consequently, the choice of composition with respect to the phase boundary is decisive for the electrical and microstructural behaviour.

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Section: Discussionsupporting

confidence: 84%

Microstructure and Electrical Properties of Mn-Ni-In Spinels

Metzmacher

Groen

Reaaney

2000

phys. stat. sol. (a)

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“…The same type of twinning has previously been observed on a microscopic scale in Mn 3 O 4 grown at temperatures above the cubic-to-tetragonal transition. 34 The twin domains of the flux-grown crystals studied in this report are macroscopic (several mm in size) and much larger than the laser spot size (∼ 50 µm) used in the Raman scattering experiments performed here. Consequently, we were able to obtain Raman spectra from single-domain regions of these samples; we therefore refer to these crystals as 'untwinned' or 'single-domain' crystals.…”

Section: A Sample Preparationmentioning

confidence: 99%

Effects of magnetic field and twin domains on magnetostructural phase mixture inMn3O4: Raman scattering studies of untwinned crystals

et al. 2016

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The ferrimagnetic spinel Mn3O4 exhibits large and anisotropic changes in electronic and structural properties in response to an applied magnetic field. These changes are thought to result from the field-dependent tuning-via strong spin-lattice coupling-between two nearly degenerate magnetostructural phases. Recent variable-magnetic-field studies of Mn3O4 have been performed on melt-grown crystals, which can exhibit twin domains due to a Jahn-Teller structural transition below the melting temperature. Because of the near degeneracy of the magnetostructural phases, however, strain associated with the twin domains likely affects the magnetic responses of Mn3O4. In this report, we present a variable-magnetic-field Raman scattering study of untwinned Mn3O4 crystals grown out of a flux below the Jahn-Teller structural transition. We measure distinct q = 0 magnetic and vibrational excitation spectra for each isolated magnetostructural phase of untwinned Mn3O4 crystals and determine the symmetries of the observed excitations. We determine how the magnetostructural phase mixture changes in response to magnetic fields applied in the magnetic easy plane. Lastly, by comparing results on flux-and melt-grown Mn3O4 crystals, we show that the intrinsic mixture of the two magnetostructural phases is indeed strongly influenced by the presence of twin domains.

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“…In Mn 2.02 Co 0.98 O 4 , a ′ and c are 0.8095 and 0.9205 nm. So,

2 φ = 2 arctan \frac{0.8095}{0.9205} = 82 . 66^{\circ}

The magnitude of shear for the

\{112\} false⟨ 11 \bar{1} false⟩

twinning is expressed as:

s = \frac{\sqrt{2} ({normalτ}^{2} - 2)}{2 τ}

where τ is the axial ratio, τ = c / a = 1.608. So, s = 0.2575.…”

Section: Resultsmentioning

confidence: 99%

“…Similarly, the twins may also have particularly effect on the electrical properties of electronic materials. In spinel semiconductors, especially in the manganates, twins are observed by some researchers using TEM, however, only a few studies focused on the forming mechanism of twins and twinning elements. Hence, it is necessary to further study the defects in manganates.…”

Section: Introductionmentioning

confidence: 99%

“…The quenched transition‐metal manganates have similar microstructures to their raw material, hausmannite Mn 3 O 4 . The lattice defects in hausmannite have been systematically studied by Couderc . Bordeneuve, et al prepared bulk single‐phase Mn 3− x Co x O 4 (0.98 ≤ x ≤ 2.93) ceramics by conventional sintering method or by spark plasma sintering method and studied the relationships between electrical properties and Co content.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Multiply Twins in Mn_2.02Co_0.98O₄ Ceramic by Means of Transmission Electron Microscopy

Liu

Lyu

2016

J. Am. Ceram. Soc.

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Mn2.02Co0.98O4 ceramic with tetragonal spinel structure was prepared by solid‐state coordination reaction method. The phase and microstructure were studied using X‐ray diffractometer (XRD) and transmission electron microscope (TEM), respectively. The results show that the Mn2.02Co0.98O4 ceramic exhibits tetragonal spinel structure owing to imperfect quenching. Several kinds of defects were formed in the sample due to the phase transition from cubic spinel at high temperature to tetragonal spinel at room temperature. Two types of {112} twin wall were found in the quenched Mn2.02Co0.98O4 ceramic. The presence and the characteristics of twins were investigated. The twins arranged in a cyclic triangle form and the twin boundaries were parallel to (112) plane or (1¯12) plane. The possible mechanism for twinning arrangement in the triangle form was proposed according to some crystal geometry model analysis.

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A transmission electron microscopy study of lattice defects in Mn₃O₄ hausmannite

Cited by 18 publications

References 22 publications

Microstructure and Electrical Properties of Mn-Ni-In Spinels

Microstructure and Electrical Properties of Mn-Ni-In Spinels

Effects of magnetic field and twin domains on magnetostructural phase mixture inMn3O4: Raman scattering studies of untwinned crystals

Investigation of Multiply Twins in Mn_2.02Co_0.98O₄ Ceramic by Means of Transmission Electron Microscopy

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A transmission electron microscopy study of lattice defects in Mn3O4 hausmannite

Cited by 18 publications

References 22 publications

Microstructure and Electrical Properties of Mn-Ni-In Spinels

Microstructure and Electrical Properties of Mn-Ni-In Spinels

Effects of magnetic field and twin domains on magnetostructural phase mixture inMn3O4: Raman scattering studies of untwinned crystals

Investigation of Multiply Twins in Mn2.02Co0.98O4 Ceramic by Means of Transmission Electron Microscopy

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Product

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A transmission electron microscopy study of lattice defects in Mn₃O₄ hausmannite

Investigation of Multiply Twins in Mn_2.02Co_0.98O₄ Ceramic by Means of Transmission Electron Microscopy