Magnetic properties of the ZnMn2O4-NiMn2O4system

Bhandage, G. T.; Keer, H. V.

doi:10.1088/0022-3719/11/6/008

Cited by 20 publications

(5 citation statements)

References 7 publications

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“…The spin arrangement for CoMn 2 O 4 is reported similar to Mn 3 O 4 [33], a ferrimagnetic spinel evidencing triangular spin arrangement as suggested by Yafet and Kittel rather than obeying Neel's antiparallel spin arrangement [27,33]. Further, it has been reported that when manganese ions are substituted with magnetic ions like Co in Mn 3 O 4 , the complex magnetic behaviour is observed due to the exchange interaction among two different lattice sites [34][35][36][37]. The exchange interaction among the lattice sites results in the competition between triangular spin arrangement of Mn 3+ at octahedral site and collinear spin arrangement of Co 2+ /Mn 2+ at tetrahedral site.…”

Section: Introductionsupporting

confidence: 56%

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn₂O₄ nanoparticles

et al. 2023

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CoMn2O4 nanoparticles synthesized through facile co-precipitation technique, exhibit a mixed phase of tetragonal and cubic at room temperature. Rietveld fitting of the XRD pattern specifies 91.84% of the tetragonal phase and 8.16% of the cubic phase. Raman spectra and selected area electron diffraction pattern further confirm the structure. Transmission electron micrograph confirms the semi-spherical shape of the particles with average diameter 95 nm, are polycrystalline in nature. While 97% of Mn3+ and 3% of Co3+ occupy the octahedral site in the tetragonal phase, 52% of Mn3+ and 48% of Co2+ occupy the octahedral site in the cubic phase. XPS analysis further confirms the presence of both +2 and +3 oxidation states of Co and Mn. Magnetic measurement shows two magnetic transitions, Tc1 at 165 K and Tc2 at 93 K corresponding to paramagnetic to a lower magnetically ordered ferrimagnetic state followed by a higher magnetically ordered ferrimagnetic state, respectively. While Tc1 could be due to the cubic phase having inverse spinel structure, Tc2 is attributed to the tetragonal phase with normal spinel. The non-collinear triangular spin canting configuration of Mn3+ cations in octahedral sites while results in large magnetization near Tc2, the decrement in magnetization at the vicinity of Tc1 indicates the decrement in Mn3+ in octahedral site, well corroborated with XRD. In contrast to general temperature dependent HC observed in ferrimagnetic material, an unusual temperature dependent HC with high spontaneous exchange bias of 2.971 kOe and conventional exchange bias of 3.316 kOe at 50 K are observed. Interestingly, a high vertical magnetization shift (VMS) of 2.5 emu/g is observed at 5 K, attributed to the Yafet-Kittel spin structure of Mn3+ in the octahedral site. Such VMS has the potential to revolutionize the future of ultrahigh density magnetic recording technology. 

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Section: Introductionsupporting

confidence: 56%

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn₂O₄ nanoparticles

et al. 2023

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“…The ZFC-FC behavior for ZnMn 2 O 4 is much more complex than the other samples in the solid solution, and has been the subject of continued investigation for many years. 35,38,39,40,41,42 Salient features that have remained consistent are Curie-Weiss paramagnetism above room temperature, with a phase transition between 230 K and 290 K that has been detected in specific heat 38,43 and Young's modulus 36 measurements. In our measurements As Mn 2+ is substituted into the end member ZnMn 2 O 4 , ferrimagnetism is induced and can be illustrated by normalizing the FC magnetization using the results of fitting the high-temperature susceptibility to the Curie-Weiss law.…”

Section: Resultsmentioning

confidence: 84%

Intrinsic exchange bias inZnxMn3−xO4
Shoemaker
¹
,
Rodriguez
²
,
Seshadri
³

et al. 2009
Phys. Rev. B
32
3
25
0
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Bulk specimens of the hetaerolite solid solution ZnxMn3−xO4 with x = 0, 0.25, 0.5, 0.75, and 1 have been prepared as homogeneous, phase-pure polycrystalline samples as ascertained by neutron diffraction measurements. Samples with x = 0.25, 0.5, and 0.75 exhibit shifted magnetic hysteresis loops at low temperature, characteristic of exchange bias typically seen in magnetic composites. We propose that the unusual magnetic behavior arises as a result of a nanoscale mixture of ferrimagnetic and antiferromagnetic regions that are distinct but lack long-range order. While some glassy behavior is seen in AC magnetic measurements, its magnitude is not sufficient to account for the observed dramatic exchange bias. Furthermore, isothermal and thermoremanent magnetization measurements distinguish this material from a pure spin glass. The title system offers insights into the alloying of a ferrimagnet Mn3O4 with an antiferromagnet ZnMn2O4 wherein distinct magnetic clusters grow and percolate to produce a smooth transition between competing orders. PACS numbers:arXiv:0906.3534v2 [cond-mat.mtrl-sci]

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“…However, for Zn x/2 Ge 1−x/2 [Co 1−x Mn x ] 2 O 4 , Wickham reports x = 0.65, [61] and Bhandage reports x = 0.70 for Zn x/2 Mn 1−x/2 [Ni 1−x Mn x ] 2 O 4 . [62] The wide spread in critical concentrations of Mn 3+ can be explained by the differences in JT splitting energies found by X-ray absorption spectroscopy on AMn 2 O 4 spinels by Noh, et al [22] In essence, the energy drop from JT distortion around Mn 3+ on the spinel B site is very senstive to changes in chemical pressure.…”

Section: Average Structure Via Reciprocal-space Analysismentioning

confidence: 99%

Total-scattering descriptions of local and cooperative distortions in the oxide spinelMg1−xCuxCr2O
Shoemaker
¹
,
Seshadri
²

2010
Phys. Rev. B
28
4
22
0
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The normal spinel oxide MgCr2O4 is cubic at room temperature while the normal spinel CuCr2O4 is tetragonal as a consequence of the Jahn-Teller activity of Cu 2+ on the tetrahedral sites. Despite different end-member structures, a complete solid solution of Mg1−xCuxCr2O4 can be prepared with compounds of composition x = 0.43 displaying a first-order phase transition at room temperature. Reverse Monte Carlo analysis of total neutron scattering on data acquired between 300 K and 15 K on samples with x = 0.10, 0.20, and 0.43 provides unbiased local and average structure descriptions of the samples, including an understanding of the transition from local Jahn-Teller distortions in the cubic phase to cooperative distortions that result in a tetragonal structure. Distributions of continuous symmetry measures help to understand and distinguish distorted and undistorted coordination around the tetrahedral site in the solid solutions. Magnetic exchange bias is observed in field-cooled hysteresis loops of samples with dilute Cu 2+ concentration and in samples with tetragonal-cubic phase coexistence around 300 K.

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Magnetic properties of the ZnMn₂O₄-NiMn₂O₄system

Cited by 20 publications

References 7 publications

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn₂O₄ nanoparticles

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn₂O₄ nanoparticles

Intrinsic exchange bias inZnxMn3−xO4
Shoemaker
¹
,
Rodriguez
²
,
Seshadri
³

et al. 2009
Phys. Rev. B
32
3
25
0
View full text Add to dashboard Cite

Total-scattering descriptions of local and cooperative distortions in the oxide spinelMg1−xCuxCr2O
Shoemaker
¹
,
Seshadri
²

2010
Phys. Rev. B
28
4
22
0
View full text Add to dashboard Cite

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Magnetic properties of the ZnMn2O4-NiMn2O4system

Cited by 20 publications

References 7 publications

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn2O4 nanoparticles

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn2O4 nanoparticles

Intrinsic exchange bias inZnxMn3−xO4Shoemaker1, Rodriguez2, Seshadri3 et al. 2009Phys. Rev. B323250View full textAdd to dashboardCite

Total-scattering descriptions of local and cooperative distortions in the oxide spinelMg1−xCuxCr2OShoemaker1, Seshadri2 2010Phys. Rev. B284220View full textAdd to dashboardCite

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Magnetic properties of the ZnMn₂O₄-NiMn₂O₄system

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn₂O₄ nanoparticles

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn₂O₄ nanoparticles

Intrinsic exchange bias inZnxMn3−xO4
Shoemaker
¹
,
Rodriguez
²
,
Seshadri
³

et al. 2009
Phys. Rev. B
32
3
25
0
View full text Add to dashboard Cite

Total-scattering descriptions of local and cooperative distortions in the oxide spinelMg1−xCuxCr2O
Shoemaker
¹
,
Seshadri
²

2010
Phys. Rev. B
28
4
22
0
View full text Add to dashboard Cite