A low-voltage magnetic nanorelay design

Abstract

The remarkable elastic properties and metallic conductivity of carbon nanotubes (CNTs) allow them to be used as parts of nanoelectromechanical systems1–5 and many different electromechanical nanorelays have already been constructed in a wide range of designs. These are based on the crossbar relative position of two carbon nanotubes,6 cantilevered7, 8 and suspended9 nanotubes, telescopic extension of nanotubes,10, 11 and a magnetic shuttle inside a carbon nanotube.12 These nanorelays are controlled by an electric field and require voltages between one and tens of volts for operation. These relatively high voltages have several disadvantages, including parasitic charging. In the last few years, researchers have discovered how to obtain a variety of endofullerenes (a fullerene acting as a cage for an atom or cluster of atoms) and ‘nanotube peapods’ (nanotubes filled with fullerenes), including nanotube peapods filled with magnetic endofullerenes,13–16 even in macroscopic amounts.17 The magnetic moments Mef of many fullerenes with encapsulated magnetic atoms are known,13, 18 and the largest belongs to the fullerene C80 filled with tri-holmium nitride, known as (Ho3N)@C80. For this endofullerene, Mef is equal to 21 Bohr magnetons ( B). This large magnetic moment and the metallic conductivity of CNTs make it possible to construct a magneticfield-sensitive element by placing endofullerenes inside a CNT. We propose a new type of nanorelay based on peapod CNTs with encapsulated magnetic endofullerenes. This allows us to disconnect control and controlled circuits, analogously to known19 macroscopic reed switches. We have calculated the operating parameters of such a novel nanorelay operated with a magnetic field, based on two (Ho3N)@C80@CNT(21,21) Figure 1. The scheme of the reed switch (magnetically operated nanorelay) based on two (21,21) CNTs filled with endofullerenes (Ho3N)@C80 with magnetic momentsMef D 21 B. Here 1 is the controlled circuit, 2 is the electrode with the attached peapod nanotube, 3 is the wire passing the current I through it and used for inducing the magnetic field with the induction B , which brings tips of the nanotubes into contact with each other.