Crystal Deformation of Copper and Nickel Chromite System

Kino, Yoshihiro; Miyahara, Syôhei

doi:10.1143/jpsj.21.2732

Cited by 36 publications

(10 citation statements)

References 2 publications

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“…This is in good agreement with the results of Kino and Miyahara. 17 The strong increase of TS1 correlates with the degree of tetragonal distortions, which is much stronger in CuCr2O4 than in NiCr2O4. Further in Fig.…”

Section: Structural and Magnetic Phase Transitions Of Ni1xcuxcr2o4mentioning

confidence: 96%

Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated systemNi1−xCuxC
Reehuis
¹
,
Tovar
²
,
Többens
³

et al. 2015
Phys. Rev. B
37
10
45
0
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Competing Jahn-Teller distortions combined with geometrical frustration give rise to a rich phase diagram as a function of x(Cu) and temperature in the spinel system Ni1xCuxCr2O4. The Jahn-Teller distortion of the end members acts in opposite ways with an elongation of the NiO4 tetrahedra resulting in a structural transition at TS1 = 317 K in NiCr2O4, but a flattening in the CuO4 tetrahedra at TS1 = 846 K in CuCr2O4, in both cases the symmetry is lowered from cubic (

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Section: Structural and Magnetic Phase Transitions Of Ni1xcuxcr2o4mentioning

confidence: 96%

Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated systemNi1−xCuxC
Reehuis
¹
,
Tovar
²
,
Többens
³

et al. 2015
Phys. Rev. B
37
10
45
0
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“…The effect of Cu 2+ occupancy on T JT and the electronic or magnetic properties remains sparesly investigated. [18][19][20] We expect there should be key differences between JT activity on the A and B sites of spinel. While BO 6 octahedra are edge-sharing and form a pyrochlore sublattice, the AO 4 tetrahedra are isolated from each other in a diamond sublattice.…”

Section: Introductionmentioning

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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“…227). When lowering the temperature, the symmetry of the nickel chromite decreases to tetrahedral at 320 K, while the cobalt chromite remains cubic down to 10 K. [7][8][9][10][11][12][13][14][15][16][17][18][19] In NiCr 2 O 4 , the phase transition between cubic and tetragonal states (the C-T transition) is of the first-order type, near to second-order type phase transition, with the tetragonal form relating to ferroelastics. It is driven by a cooperative Jahn-Teller effect in the array of Ni 2+ cations in tetrahedral positions [for the Cr 3+ (3d 3 ) cations the Jahn-Teller effect in the octahedral crystal field is not observed].…”

mentioning

confidence: 99%

Ferroelectricity in spinel solid solution Co0.8Ni0.2Cr2O
Буш
¹
,
Shkuratov
²
,
Kamentsev
³

et al. 2012
Phys. Rev. B
14
1
11
0
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Temperature dependencies of dielectric permittivity and loss tangent (at frequencies 0.1-200 kHz) together with thermally stimulated depolarization currents, magnetization, and Mössbauer spectra of ceramic solid solutions Co 1−x Ni x Cr 2 O 4 (x = 0, 0.2, 0.4, 0.6, 1.0) are studied at temperatures from 80 to 350 K. We find evidence of two reversible phase transitions located at T 1 and T 2 (220 and 245 K, respectively, for x = 0.2), of occurrence of pyroelectric properties below T 2 , as well as of a phase transition to magnetically ordered state of ferrimagnetic type (below 86 K for x = 0.2). The obtained results evidence that the compounds possess, additionally to magnetic, ferroelectric properties and are thus new members in the family of multiferroics.Spinel compounds with Jahn-Teller cations reveal structural phase transitions caused by removal of the orbital degeneracy leading to ordering of the d orbitals and to lowering of the crystal lattice symmetry. As a result, some low-symmetry phases become polar and reveal multiferroic properties. [1][2][3][4][5][6][7][8][9][10][11][12] Most detailed studies of such multiferroicity were performed for magnetite (Fe 2+ Fe 2 3+ O 4 ) whose low-symmetry phase is monoclinic (Cc) 5 ; here, switching between magnetic and electrical orderings can be driven by both magnetic and electric fields. 1-4 Recently, similar studies were performed also on chromites, like CoCr 2 O 4 . 7-12 Cobalt CoCr 2 O 4 and nickel NiCr 2 O 4 chromites belong to the spinel family with the general formula AB 2 O 4 in which Co 2+ (3d 7 ) or Ni 2+ (3d 8 ) bivalent cations occupy tetrahedrally coordinated by oxygen A positions and the Cr 3+ trivalent cations-octahedral positions. 6-14 These compounds crystallize, at rather high temperatures, into a cubic phase with the space group F d3m (No. 227). When lowering the temperature, the symmetry of the nickel chromite decreases to tetrahedral at 320 K, while the cobalt chromite remains cubic down to 10 K. 7-19 In NiCr 2 O 4 , the phase transition between cubic and tetragonal states (the C-T transition) is of the first-order type, near to second-order type phase transition, with the tetragonal form relating to ferroelastics. It is driven by a cooperative Jahn-Teller effect in the array of Ni 2+ cations in tetrahedral positions [for the Cr 3+ (3d 3 ) cations the Jahn-Teller effect in the octahedral crystal field is not observed]. In ACr 2 O 4 , the transition into the ferrimagnetic state takes place at T N = 93 K for A = Co and at T N = 70 К for A = Ni. 6,9,11,[20][21][22] In spite of the fact that the considered complex oxides reveal intriguing elastic, electrical, magnetic, catalytic, and other physical properties and attract much attention, 1-25 there is practically no data in the literature on their dielectric characteristics. In this paper we present our results on the first measurements of the temperature-frequency behavior of the complex dielectric permittivity ε * = ε 1 + iε 2 , loss tangent tgδ = ε 2 /ε 1

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Crystal Deformation of Copper and Nickel Chromite System

Cited by 36 publications

References 2 publications

Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated systemNi1−xCuxC
Reehuis
¹
,
Tovar
²
,
Többens
³

et al. 2015
Phys. Rev. B
37
10
45
0
View full text Add to dashboard Cite

Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated systemNi1−xCuxC
Reehuis
¹
,
Tovar
²
,
Többens
³

et al. 2015
Phys. Rev. B
37
10
45
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

Ferroelectricity in spinel solid solution Co0.8Ni0.2Cr2O
Буш
¹
,
Shkuratov
²
,
Kamentsev
³

et al. 2012
Phys. Rev. B
14
1
11
0
View full text Add to dashboard Cite

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Crystal Deformation of Copper and Nickel Chromite System

Cited by 36 publications

References 2 publications

Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated systemNi1−xCuxCReehuis1, Tovar2, Többens3 et al. 2015Phys. Rev. B3710450View full textAdd to dashboardCite

Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated systemNi1−xCuxCReehuis1, Tovar2, Többens3 et al. 2015Phys. Rev. B3710450View 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

Ferroelectricity in spinel solid solution Co0.8Ni0.2Cr2OБуш1, Shkuratov2, Kamentsev3 et al. 2012Phys. Rev. B141110View full textAdd to dashboardCite

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Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated systemNi1−xCuxC
Reehuis
¹
,
Tovar
²
,
Többens
³

et al. 2015
Phys. Rev. B
37
10
45
0
View full text Add to dashboard Cite

Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated systemNi1−xCuxC
Reehuis
¹
,
Tovar
²
,
Többens
³

et al. 2015
Phys. Rev. B
37
10
45
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

Ferroelectricity in spinel solid solution Co0.8Ni0.2Cr2O
Буш
¹
,
Shkuratov
²
,
Kamentsev
³

et al. 2012
Phys. Rev. B
14
1
11
0
View full text Add to dashboard Cite