Effects of particle size on the electrical properties of NdFeO 3 nanoparticles
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Effects of particle size on the electrical properties of NdFeO3 nanoparticles Qiaoqiao Dong1, Yuchang Su1,* Congcong Shi1 1
, Yanzi Liu1, Jing Zhang1, Hongzhi Zhang1, and
School of Materials Science and Engineering, Central South University, Changsha 410083, People’s Republic of China
Received: 28 August 2020
ABSTRACT
Accepted: 15 October 2020
In this paper, NdFeO3 nanoparticles were synthesized by the co-precipitation method. The particle size of NdFeO3 nanoparticles was controlled by changing the NaOH concentration in the co-precipitation method, mainly because NaOH concentration could control grain growth. The samples were characterized by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FESEM). They were found that with the change of NaOH concentration, the lattice parameters and cell volume of NdFeO3 nanoparticles changed little, but the average particle size ranged from * 100 to * 142 nm. And the influence of particle size on electrical properties of samples was also explored. The results showed that the dielectric constant of the sample increased with the decrease of the average particle size, and the dielectric loss decreases. When the average particle size was * 100 nm and the frequency was 103 Hz, the dielectric constant (e0 ) was at most (* 1.4 9 104) at room temperature, indicating that it had potential applications in dielectric capacitors. In addition, the conduction mechanism of NdFeO3 nanoparticle was studied by frequency dependence of AC conductivity. The effect of the grain and grain boundaries of NdFeO3 nanoparticles on the electrical properties of material was observed in complex impedance spectroscopy. The grain boundary resistance played a leading role in the resistance of the material, and the values of resistance increased with the decrease of the particle size.
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
1 Introduction Perovskite-type oxides (ABO3) have become a hot topic due to their diversity of structure, chemical composition, and magnetoelectric coupling effect [1]. A and B represent mostly rare earth elements and transition metal elements, respectively [2]. The A-
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https://doi.org/10.1007/s10854-020-04695-8
type atoms affect physical properties through steric affects, while the size, valence, and spin state of Btype atoms have important effects on its magnetism and electronic properties, such as dielectric properties and conductivity [3, 4]. In the ABO3, the interaction of magnetic field strength exists in A–A, A–B, and B–B, and the interaction between them increases
J Mater Sci: Mater Electron
successively, which mainly depends on the electron configuration, band strength, bond length, and bond angle [5]. In addition, the stability of ABO3 perovskite type structure can be characterized by tolerance factor (s), defined as RA þ RO s ¼ pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ; 2ðRB þ RO Þ
ð1Þ
where RA and RB are the ionic radius of A and B ions, respectively; RO is the oxygen ion radius
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