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Evaluation of low magnetic field magnetocapacitance effect in Ni–NiO inhomogeneous medium

Singh, S and Poojari, J and Bhat, V and Mallikarjun, R and Athikundil Kayakkulam, S and Shinde, KP and Park, JS and Jo, Y and Kumar, PSA and Joshi, RS (2023) Evaluation of low magnetic field magnetocapacitance effect in Ni–NiO inhomogeneous medium. In: Applied Physics A: Materials Science and Processing, 129 (10).

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Official URL: https://doi.org/10.1007/s00339-023-06915-4


Low field magnetocapacitance (MC) effect is studied in an inhomogeneous medium with ferromagnetic conducting and antiferromagnetic semiconducting content. The inhomogeneous medium was synthesized by solution combustion method with variation of fuel to oxidant ratio. Antiferromagnetic pure NiO and ferromagnetic Ni dispersed in NiO matrix were formed using single step combustion due to induced self-reduction in precursors. A crystallographic compression was observed in the NiO lattice with reduced Ni. The magnetocapacitance effect was evaluated in these, using relaxation analysis of the magneto-dielectric dispersion with modified Havriliak�Negami model. It was observed that the permittivity relaxation time was of the order of ~ 16 to 35 ms at 1.2 kOe in capacitors with magnetic content whereas in pure NiO it was of the order of ~ 65 μs. The analysis using macrospin approximation indicated dipole�dipole-like interaction or interface dominant MC of the order of + 7.5 at 1.2 kOe in pure NiO, whereas in Ni�NiO it was exchange mediated at higher frequencies and intermediate magnetic fields with � 4.15 MC at 1.2 kOe. The dominance of spin accumulation over spin dependent scattering was established by comparing MC with magnetoresistance (MR). The MR content was found to be of the order of ~ � 4 for capacitors with ferromagnetic component in the low field region indicating significant spin dependent scattering along with spin accumulation. Whereas in pure NiO the MR was of the order of � 0.6 indicating very low spin dependent scattering. AC reactance of the device was also evaluated to establish the interactions and strength of spin dependent scattering in these capacitors. The power analysis of magnetocapacitance indicated that Ni�NiO capacitors had coherent spin scattering with increased exchange mediated nonlinear, non-local interaction (long range) and magnetoelectric coupling whereas in NiO it was local interaction mediated by pronounced dipolar coupling. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.

Item Type: Journal Article
Publication: Applied Physics A: Materials Science and Processing
Publisher: Springer Science and Business Media Deutschland GmbH
Additional Information: The copyright for this article belongs to the Springer Science and Business Media Deutschland GmbH.
Keywords: Antiferromagnetism; Coherent scattering; Combustion; Ferromagnetic materials; Ferromagnetism; Magnetic fields; Nickel oxide, Antiferromagnetics; Ferromagnetics; Inhomogeneous medium; Magneto-dielectric relaxation; Magneto-dielectrics; Magnetocapacitance; Magnetocapacitance effects; Magnetoelectric couplings; Solution combustion; Spin dependent scattering, Dielectric relaxation
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 21 Nov 2023 09:35
Last Modified: 21 Nov 2023 09:35
URI: https://eprints.iisc.ac.in/id/eprint/83193

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