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Abstract：
Electric, dielectric, and optical (band gap) properties of pure multiferroic as well as La- and Ni-doped SrFe12O19 (SFO) (at different sites) are investigated using a microscopic model and Green\'s function technique. The concentration dependence of the polarization P is considered for substitution of rare earths ions on the Sr sites. For a small La ion doping concentration, x = 0.1, La-doped SFO is ferroelectric, whereas for a larger doping concentration, for example x = 0.5, it is antiferroelectric. The real part of the dielectric constant ϵ increases with an increasing magnetic field h. ϵ decreases with an increasing frequency and La dopants. Therefore, La-doped SFO is suitable for microwave application with a low dielectric constant. The magnetic properties of pure SFO NPs are also studied. Ni doping at the Fe site of SFO leads to enhanced ferroelectric polarization and dielectric constant. The band gap decreases or increases by substitution of Ni or In ions on the Fe site, respectively. The results reveal that the tuned band gap of Ni-doped SFO makes it a crucial candidate for optoelectronic and solid oxide fuel cell applications.
摘要：
电动,电介质,使用微观模型和格林函数技术研究了纯多铁性以及La和Ni掺杂的SrFe12O19（SFO）（在不同位置）的光学（带隙）性质。极化P的浓度依赖性被认为是在Sr位点上取代稀土离子。对于小的La离子掺杂浓度，x=0.1，La掺杂的SFO是铁电的，而对于更大的掺杂浓度，例如x=0.5，它是反铁电的。介电常数ε的实部随着磁场h的增加而增加。ε随着频率和La掺杂剂的增加而减小。因此,La掺杂的SFO适用于具有低介电常数的微波应用。还研究了纯SFONPs的磁性。在SFO的Fe位点掺杂Ni导致增强的铁电极化和介电常数。通过在Fe位点上取代Ni或In离子，带隙减小或增加，分别。结果表明，掺杂Ni的SFO的调谐带隙使其成为光电和固体氧化物燃料电池应用的关键候选物。
