Structure and magnetic phase transitions in (Ni1−Co )Cr2O4 spinel nanoparticles

Mohanty, P.; Venter, А.M.; Sheppard, C. J.; Prinsloo, A. R. E.

doi:10.1016/j.jmmm.2019.166217

Cited by 13 publications

(7 citation statements)

References 28 publications

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“…However, upon substituting Ni at Co site, the transitions appeared to be smeared out (see Fig. 15 (b) and (d)) using knee point method as described previously [16,17]. Comparing T C values found for the films compared with the powder samples previously measured are given in Table VII.…”

Section: (A) and (C))mentioning

confidence: 79%

“…The T C values were determined to be 104.5 ± 0.4 K and 108.5 ± 0.6 K for films grown on the MgAl 2 O 4 (100) and MgO (100) substrates, respectively. These values were determined, using knee point method as described previously [16,17] (see insets of figures 15(b) and (d)). The T C values found for the films are given in table 7 for comparison with those obtained for the powder samples previously measured and also determined using the knee-point method as reported previously [16,17].…”

Section: Resultsmentioning

confidence: 99%

“…Comparing T C values found for the films compared with the powder samples previously measured are given in Table VII. These were determined using the knee-point method as reported previously for all the samples [16,17]. The reported T C values for CoCr 2 O 4 films grown on MgAl 2 O 4 (100)…”

Section: (A) and (C))mentioning

confidence: 99%

“…Recently, magnetic and electronic properties of (Ni 1x Co x )Cr 2 O 4 , with 0 ≤ x ≤ 1, were reported [16,17]. Substituting Co at the Ni site effectively changed the magnetic transition temperatures [16,17]. In case of nanoparticles of (Co 1x Ni x )Cr 2 O 4 , with x = 0.5 and 0.25, showed modified magnetic transition temperatures along with wasp-waist like features observed in the magnetization as a function of applied magnetic field measurements at low temperatures [18].…”

Section: Introductionmentioning

confidence: 99%

“…However, reports on doped CoCr 2 O 4 thin films are lacking. Recently, magnetic and electronic properties of (Ni 1-x Co x )Cr 2 O 4 , with 0 ⩽ x ⩽ 1, were reported [16,17]. Substituting Co at the Ni site effectively changed the magnetic transition temperatures [16,17].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films

Mohanty¹,

Chowdhury²,

Choudhary³

et al. 2020

Nanotechnology

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Cubic spinel CoCr 2 O 4 has attained recent attention due to its multiferroic properties. However, the Co site substitution effect on the structural and magnetic properties has rarely been studied in thin film form. In this work, the structural and magnetic properties of Co 1x Ni x Cr 2 O 4 (x = 0, 0.5) epitaxial thin films deposited on MgAl 2 O 4 (100) and MgO (100) substrates to manipulate the nature of strain in the films using pulsed laser deposition (PLD) technique are presented. The epitaxial nature of the films was confirmed through X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS) measurements. Raman measurements revealed a disappearance of characteristic A 1g and F 2g modes of the CoCr 2 O 4 with increase in the Ni content. Atomic force microscopy (AFM) studies show a modification of the surface morphology upon Ni substitution. Magnetic measurements disclose that the ferrimagnetic Curie temperature (T c ) of the CoCr 2 O 4 in thin film grown on MgAl 2 O 4 (100) and MgO (100) substrates were found to be 100.6 ± 0.5 K and 93.8 ± 0.2 K, respectively. With Ni substitution the transition temperatures significantly get enhanced from that of CoCr 2 O 4 . X-ray photoelectron spectroscopy (XPS) suggests Cr 3+ oxidation states in the films, while Co ions are present in a mixed Co 2+ /Co 3+ oxidation state. The substitution of Ni at Co site significantly modifies the line shape of the core level as well as the valence band. Ni ions are also found to be in a mixed 2+/3+ oxidation state. O 1s core level display asymmetry related to possible defects like oxygen vacancies in the films. CoCr 2 O 4 is a ferrimagnetic spinel compound with complex magnetic interactions at low temperatures [1]. The magnetic cations Co 2+ and Cr 3+ ions occupy the tetrahedral A and octahedral B sites, respectively, of the spinel structure [1]. Below Curie temperature (T C = 93 K), a collinear ferrimagnetic ordering occurs, with further lowering the temperature to 26 K (T S ) the compound develops a short-range-ordered (SRO) spiral component [1]. Theoretical calculations has also evidenced the T S feature due to the nesting of the Fermi surface having high degree of magnetic instability in the system associated with the nesting vector q along the [110] direction [2]. Recent experiments have shown the size dependence of these magnetic transitions [3]. Below a critical particle size of d c , spiral = 4.4 (1) nm, the spiral ordering vanishes [3] and for size less than d c , col = 3.3 (1) nm, the collinear magnetic order disappears [3]. A lock-in transition at a temperature T L = 15 K appears because of the incommensurate-to-commensurate magnetic phase transition [1]. At T L the period of the spin spiral eventually "locks in" to the lattice parameter [1]. This spiral component is responsible for inducing the multiferroicity in CoCr 2 O 4 [1]. Structurally, CoCr 2 O 4 is stable and remains cubic with space group Fd ̅ m at all temperatures as the sample is cooled down to 10 K [4].On the other hand for NiCr 2 O 4 the crystal ...

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Section: (A) and (C))mentioning

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Section: (A) and (C))mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films

Mohanty¹,

Chowdhury²,

Choudhary³

et al. 2020

Nanotechnology

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Effect of Cobalt on NiCr2O4: Calculation of Critical Temperature and Exchange Interactions

Masrour

2023

SpringerBriefs in Materials

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Polyacrylamide gel synthesis, characterization, and optical properties of Co1-xNixCr2O4 spinel nanopigment

Ahmadyari-Sharamin

Hassanzadeh-Tabrizi

2021

J Sol-Gel Sci Technol

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Structure and magnetic phase transitions in (Ni1−Co )Cr2O4 spinel nanoparticles

Cited by 13 publications

References 28 publications

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films

Effect of Cobalt on NiCr2O4: Calculation of Critical Temperature and Exchange Interactions

Polyacrylamide gel synthesis, characterization, and optical properties of Co1-xNixCr2O4 spinel nanopigment

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Structure and magnetic phase transitions in (Ni1−Co )Cr2O4 spinel nanoparticles

Cited by 13 publications

References 28 publications

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr2O4 spinel thin films

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr2O4 spinel thin films

Effect of Cobalt on NiCr2O4: Calculation of Critical Temperature and Exchange Interactions

Polyacrylamide gel synthesis, characterization, and optical properties of Co1-xNixCr2O4 spinel nanopigment

Contact Info

Product

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About

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr₂O₄ spinel thin films