Abstract

The magnetic, electric, and dielectric properties of pure and ion-doped antiferromagnetic magnetoelectric Fe\(_2\)TeO\(_6\) (FTO) nanoparticles (NPs) are investigated using a microscopic model and the Green’s function theory. The Neel temperature \(T_N\) decreases with decreasing NP size. Due to uncompensated spins on the surface, there appears a small ferromagnetism. By different ion doping is observed also a small ferromagnetism. The magnetic properties of FTO can be changed by different ion doping at the Te or Fe places in FTO NPs. \(T_N\) is enhanced by Nb or Zr doping at the Te site, whereas by Cr doping at the Fe site, it is reduced. The polarization P of a pure FTO NP is enhanced by applying an external magnetic field. P increases with increasing magnetic field which is evidence for the multiferroism of FTO. The temperature dependence of the dielectric constant \(\epsilon \) for a pure FTO NP shows at \(T_N\) = 180 K a small peak which disappears for high-frequency values. The real part of \(\epsilon \) increases, whereas the imaginary part decreases with increasing Zr dopants in FTO at the Te site.

Graphical abstract

中文翻译：

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离子掺杂 Fe $$_2$$ TeO $$_6$$ 纳米颗粒的磁、电和介电特性

摘要

使用微观模型和格林函数理论研究了纯和离子掺杂的反铁磁磁电 Fe \(_2\) TeO \(_6\) (FTO) 纳米颗粒 (NP) 的磁、电和介电特性。尼尔温度\(T_N\)随着 NP 尺寸的减小而降低。由于表面上未补偿的自旋，出现了小的铁磁性。通过不同的离子掺杂，还观察到小的铁磁性。FTO 纳米粒子中 Te 或 Fe 位置的不同离子掺杂可以改变 FTO 的磁性能。Te位点的Nb或Zr掺杂增强了\(T_N\) ，而Fe位点的Cr掺杂则降低了\(T_N\)。纯 FTO NP 的极化P通过施加外部磁场而增强。P随着磁场的增加而增加，这是FTO多铁性的证据。纯 FTO NP 的介电常数\(\epsilon \)的温度依赖性显示，在\(T_N\) = 180 K 时有一个小峰值，该峰值在高频值下消失。随着Te位点FTO中Zr掺杂量的增加， \(\epsilon \)的实部增加，而虚部减少。

图形概要