Introduction to Nanoscience and Nanotechnology. Chris Binns

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Introduction to Nanoscience and Nanotechnology - Chris Binns


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reverse the materials and produce films of Co nanoparticles in an Fe matrix as shown in Figure 1.11b.

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      What the data clearly show is that the magnetization in the films of Fe nanoparticles embedded in Co matrices exceeds that of the Slater–Pauling curve till the density of nanoparticles reaches the percolation threshold at 25%. Then, the magnetization reduces to a value that is the weighted average of the Fe and Co bulk magnetic moments. This is due to the nanoparticles coming into contact and the Fe–Co interface reducing so that essentially there is a phase‐separated mixture. It is evident from the data for the Co nanoparticles in an Fe matrix, however, that a saturation magnetization of about 3 T can be achieved, which is significantly higher than the Slater–Pauling limit. The data in Figure 1.12 are from a material rather than isolated nanoparticles, but it is still in the form of a very thin film approximately 50 nm thick, that is, a long way from a bulk material. With big improvements in the flux from nanoparticle sources, however, there are now patented ideas to produce bulk quantities of this nanostructured alloy, which the author's group is working on at the Universidad de Castilla‐La Mancha in Spain. It is envisaged that this material will find its way into motors for all‐electric transport within eight years where it will produce at least a 20% improvement in the power to weight ratio of the motor.

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      Source: Reproduced with permission from Integran Technologies Inc. (http://www.integran.com).

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      Source: Reproduced with the permission of Elsevier Science from K. M. Youssef et al. [14].


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