Interspacing dependence of spin-dependent variable range hopping for cold-pressed Fe3O4 nanoparticles
Interspacing dependence of spin-dependent variable range hopping for cold-pressed Fe3O4 nanoparticles
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DOI：
10.1063/1.4804335
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发表时间：
2013-05
影响因子：
3.2
通讯作者：
Ningning Song;Haitao Yang;Feiming Li;Zi-An Li;W. Han;X. Ren;Yi Luo;Xiancheng Wang;C. Jin;Xiang-qun Zhang;Zhaohua Cheng
中科院分区：
文献类型：
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作者：
Ningning Song;Haitao Yang;Feiming Li;Zi-An Li;W. Han;X. Ren;Yi Luo;Xiancheng Wang;C. Jin;Xiang-qun Zhang;Zhaohua Cheng
单分散Fe 3 O 4纳米粒子（NPs）之间的接触的影响的自旋相关的输运机制进行了研究，仅改变冷压压力从20.0 MPa到5.0 GPa。在20.0 MPa下冷压的样品，电阻率ρ-T曲线与温度的关系符合log ρ <$T−1/2关系，符合Efros变程跳跃（弗赫）机制;在1.0 ~ 5.0 GPa下冷压的样品，电阻率ρ-T曲线与温度的关系符合log ρ <$T−1/4关系，符合Mott变程弗赫机制。不同的机制与纳米粒子之间的电荷能和交换能的间距依赖性有关。MonteCarlo模拟结果表明，在前一种机制中，电荷能起主导作用，而在后一种机制中，自旋相关的交换能起主导作用。
The influence of the contact between monodisperse Fe3O4 nanoparticles (NPs) on the spin-dependent transport mechanism has been investigated by only changing the cold-press pressures from 20.0 MPa to 5.0 GPa. For the sample cold-pressed under 20.0 MPa, the temperature dependence of resistivity ρ-T curve is best fitted by the log ρ ∝ T−1/2 relation, suggesting the Efros's variable range hopping (VRH) mechanism, while the ρ-T curves of the samples cold-pressed under 1.0 GPa to 5.0 GPa can be best fit with the relation of log ρ ∝ T−1/4, revealing the Mott's VRH mechanism. The different mechanisms are related to the interspacing dependence of charging energy and exchange energy between NPs. Monte Carlo simulations indicated that the charging energy plays a dominant role in the former mechanism, while the spin-dependent exchange energy is dominated in the latter one.