The origin of frustration of magnetic coupling in the NiFeCrO4 ferrite

We present crystallographic and magnetic properties of NiCr 1.98 57 Fe 0.02 O 4 by using X-ray diffractometry (XRD), vibrating sample magnetometry (VSM), and Mössbauer spectroscopy. The lattice constants a 0 were determined to be 8.318 Å. The ferrimagnetic Neel temperature (T N ) for NiCr 1.98 57 Fe 0.02 O 4 is determined to be 90 K. The Mössbauer absorption spectra for all chromites at 4.2 K show two well developed sextets superposed with small difference of hyperfine fields (H hf ) caused by Cr 3+ ions in two different magnetic sites. The values of the isomer shifts show that the charge states of Fe are Fe 3+ for all temperature range. Ni-chromites Mössbauer spectra below T N present aline broadening due to a Jahn-Teller distortion and show that spin structure behavior of Cr ions change from an incommensurate to a commensurate state.

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“…At this temperature a crystallograpic change from a cubic to tetragonal(c/a <1) transition occurs [6][7][8].…”

Section: T (K)mentioning

confidence: 97%

Mössbauer study of spin structure transformation from an incommensurate to a commensurate state

et al. 2008

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“…The bulk sample with chromium content of x = 1.0 is advised to be used as a permanent magnet, since it exhibits high coercivity. − Another interesting property of the system NiFe (2– x ) Cr x O 4 is the occurrence of the compensation point T comp at some Cr concentrations. − At this point the temperature-dependent magnetization decreases to zero even below the Neel temperature due to compensation of the magnetic moments of the A- and B-sublattices, ordered antiferromagnetically in the ground state at low temperatures. According to the Neel approach, T comp is not a point of the magnetic phase transition; however, very many anomalous effects were observed at this point, such as magnetoresistance, the magneto-optical Faraday effect, the Hall effect, coercitivity, and the magnetocalorimetric effect. − …”

Section: Introductionmentioning

confidence: 99%

Structural, Magnetic, and Electronic Properties of Mixed Spinel NiFe_2–xCr_xO₄ Nanoparticles Synthesized by Chemical Combustion

et al. 2017

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A series of nickel-chromium-ferrite NiFeCrO (with x = 1.25) nanoparticles (NPs) with a cubic spinel structure and with size d ranging from 1.6 to 47.7 nm was synthesized by the solution combustion method. A dual structure of all phonon modes revealed in Raman spectra is associated with metal cations of different types present in the spinel lattice sites. Mössbauer spectra of small NPs exhibit superparamagnetic behavior. However, the transition into the paramagnetic state occurs at a temperature that is unusually high for small particles (T is about 240 K in the d = 4.5 nm NPs). The larger NPs with d > 20 nm do not exhibit superparamagnetic properties up to the Neel temperature. From the magnetic and Mössbauer data, the cation occupation of the tetrahedral (A) and octahedral [B] sites was determined (FeNi)[NiCr]O. The saturation magnetization M in the largest NPs is about (0.98-0.95) μ, which is more than twice higher the value in bulk ferrite (Fe)[CrNi]O. At low temperatures the total magnetic moment of the ferrite coincides with the direction of the B-sublattice moment. In the NPs with d > 20 nm, the compensation of the magnetic moments of A- and B-sublattices was revealed at about T = 360-365 K. This value significantly exceeds the point T in bulk ferrites NiFeCrO (about 315 K) with the similar Cr concentration. However, in the smaller NPs NiFeCrO with d ≤ 11.7 nm, the compensation effect does not occur. The magnetic anomalies are explained in terms of highly frustrated magnetic ordering in the B sublattice, which appears due to the competition of AFM and FM exchange interactions and results in a canted magnetic structure.

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Mössbauer study of spin structure transformation from an incommensurate to a commensurate state

Choi¹,

Park²,

Kim³

et al. 2008

Icame 2007

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The origin of frustration of magnetic coupling in the NiFeCrO4 ferrite

Cited by 8 publications

References 7 publications

Mössbauer study of spin structure transformation from an incommensurate to a commensurate state

Mössbauer study of spin structure transformation from an incommensurate to a commensurate state

Structural, Magnetic, and Electronic Properties of Mixed Spinel NiFe_2–xCr_xO₄ Nanoparticles Synthesized by Chemical Combustion

Mössbauer study of spin structure transformation from an incommensurate to a commensurate state

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The origin of frustration of magnetic coupling in the NiFeCrO4 ferrite

Cited by 8 publications

References 7 publications

Mössbauer study of spin structure transformation from an incommensurate to a commensurate state

Mössbauer study of spin structure transformation from an incommensurate to a commensurate state

Structural, Magnetic, and Electronic Properties of Mixed Spinel NiFe2–xCrxO4 Nanoparticles Synthesized by Chemical Combustion

Mössbauer study of spin structure transformation from an incommensurate to a commensurate state

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Product

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Structural, Magnetic, and Electronic Properties of Mixed Spinel NiFe_2–xCr_xO₄ Nanoparticles Synthesized by Chemical Combustion