Abstract

In this article, we have explored the exchange coupled behavior of MnFe₂O₄/α-Fe₂O₃ core-shell based nanocomposite systems. Four nanocomposite samples were prepared by varying weight percentage of α-Fe₂O₃ with the generic formula (1 − x) MnFe₂O₄/x α-Fe₂O₃ (x = 0.15, 0.30, 0.45 and 0.60). The existence of single spinel cubic phase of MnFe₂O₄ along with rhombohedral phase of α-Fe₂O₃ was verified by the X-ray powder diffraction profiles. The FC hysteresis loops disclosed a large amount of exchange bias (H_EB) of 1.1 kOe along with high coercivity (3.3 kOe) at 5 K for all the samples. Exchange spring type behavior was observed in hysteresis curves of entire nanocomposites. The M-T plots revealed that the blocking temperature (T_B) of entire samples was above the room temperature together with presence of strong interparticle interactions. The blocking temperature was found to shift above 300 K even in tiny size due to significant exchange bias effect.

Graphical abstract

中文翻译：

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核壳结构MnFe 2 O 4 /α-Fe 2 O 3纳米复合体系的交换偏压效应和交换弹簧型行为

摘要

在本文中，我们探讨了基于MnFe ₂ O ₄ / α -Fe ₂ O ₃核壳的纳米复合体系的交换耦合行为。四个纳米复合材料样品通过的不同的重量百分比制备α -Fe ₂ ö ₃与通式（1 - X）锰铁₂ ø ₄ / Xα -Fe ₂ ø ₃（X = 0.15，0.30，0.45和0.60）。MnFe ₂ O ₄单尖晶石立方相与α -Fe菱面体相的存在通过X射线粉末衍射图验证了₂ O ₃。对于所有样品，FC磁滞回线都显示出1.1 kOe的大量交换偏压（H _EB）和5 K时的高矫顽力（3.3 kOe）。在整个纳米复合材料的磁滞曲线中观察到交换弹簧类型的行为。的MT曲线表明，阻断温度（Ť_乙整个样本）为上述具有较强间相互作用的存在下，室温下一起。由于显着的交换偏压效应，发现封端温度即使在很小的尺寸下也可以移动到300 K以上。

图形概要