Udalov O G, Beloborodov I S
Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330, United States of America. Institute for Physics of Microstructures, Russian Academy of Science, Nizhny Novgorod, 603950, Russia.
J Phys Condens Matter. 2017 Apr 20;29(15):155801. doi: 10.1088/1361-648X/aa6181. Epub 2017 Mar 13.
We develop a theory of the exchange interaction between ferromagnetic (FM) metallic grains embedded into insulating matrix by taking into account the Coulomb blockade effects. For bulk ferromagnets separated by the insulating layer the exchange interaction strongly depends on the height and thickness of the tunneling barrier created by the insulator. We show that for FM grains embedded into insulating matrix the exchange coupling additionally depends on the dielectric properties of this matrix due to the Coulomb blockade effects. In particular, the FM coupling decreases with decreasing the dielectric permittivity of insulating matrix. We find that the change in the exchange interaction due to the Coulomb blockade effects can be a few tens of percent. Also, we study dependence of the intergrain exchange interaction on the grain size and other parameters of the system.
我们通过考虑库仑阻塞效应，建立了一种嵌入绝缘基质中的铁磁（FM）金属颗粒间交换相互作用的理论。对于被绝缘层隔开的块状铁磁体，交换相互作用强烈依赖于由绝缘体形成的隧穿势垒的高度和厚度。我们表明，对于嵌入绝缘基质中的FM颗粒，由于库仑阻塞效应，交换耦合还依赖于该基质的介电性质。特别是，FM耦合随着绝缘基质介电常数的减小而降低。我们发现，由于库仑阻塞效应导致的交换相互作用的变化可达百分之几十。此外，我们研究了颗粒间交换相互作用对晶粒尺寸和系统其他参数的依赖性。
