Transition of exchange bias from the linear to oscillatory regime with the progression of surface oxidation of Ag@FeCo@Ag core@shell@shell nanoparticles
Transition of exchange bias from the linear to oscillatory regime with the progression of surface oxidation of Ag@FeCo@Ag core@shell@shell nanoparticles
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DOI：
10.1063/1.4963343
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发表时间：
2016-10-07
影响因子：
3.2
通讯作者：
Maenosono, S.
中科院分区：
文献类型：
--
作者：
Takahashi, M.;Mohan, P.;Maenosono, S.
研究了Ag@FeCo@Ag和AgAu@FeCo@ AgAu核@壳@壳纳米粒子交换偏置场随老化时间的演化。由于部分氧化的薄（类似于2.5纳米厚）铁磁（FM）FeCo中间壳反铁磁（AFM）Co0.5Fe0.5O相，交换偏置清楚地观察到在FM和AFM层之间的界面。当AFM（v（AFM））和FM（v（FM））层的体积之比v（AFM）/v（FM）小于2.8时，交换偏置场随老化时间单调增加。然而，当v（AFM）/v（FM）> 3：6时，交换偏置场相对于v（AFM）/v（FM）表现出振荡行为。这种振荡行为可能是由于FM和AFM层之间的小界面面积，这导致AFM壳中的剩余磁化强度的波动。使用线性范围内的交换偏置场，可以灵敏地估计AFM层的厚度（即，表面氧化层）。出版社：AIP Publishing
The evolution of the exchange bias field was investigated in Ag@FeCo@Ag and AgAu@FeCo@ AgAu core@shell@shell nanoparticles as a function of aging time. Because of the partial oxidation of the thin (similar to 2.5-nm thick) ferromagnetic (FM) FeCo intermediate shell to an antiferromagnetic (AFM) Co0.5Fe0.5O phase, exchange bias was clearly observed at the interface between the FM and AFM layers. The exchange bias field monotonically increased with aging time when the ratio between the volumes of the AFM (v(AFM)) and FM (v(FM)) layers, v(AFM)/v(FM), was less than 2.8. However, the exchange bias field showed an oscillatory behavior with respect to v(AFM)/v(FM), when v(AFM)/v(FM) > 3:6. This oscillatory behavior probably results from the small interfacial area between the FM and AFM layers, which causes fluctuations of the surplus magnetization in the AFM shell. Using the exchange bias field within the linear regime, it is possible to sensitively estimate the thickness of the AFM layer (i.e., the surface oxide layer). Published by AIP Publishing.