Secondary emission yield at low-primary energies of magnetic materials for anti-multipactor applications

Secondary electron emission processes under electron bombardment are central to many effects at surfaces and interfaces, and to many in vacuum high power RF electronic devices where multipactor can be very intense [1,2]. Ferrite materials are usually used in microwave components used in space telecommunication systems, as circulators, phase-shifters, switches, and isolators. The physics of the multipactor phenomenon existing in microwave devices based on ferrite materials is an important issue and it is urgent to be researched [3]. One difficulty in the analysis of the multipactor effect in RF components containing ferrite lies on the fact that this material is an anysotropic magnetic medium controlled by an applied permanent magnetic field, which is used to magnetize the ferrite material. SEY and other properties (structure, magnetic behaviour,...) of soft-magnetic materials were studied in this work. MnZn soft ferrites magnets are suitable in the situation of frequency < 3MHz, low loss and high μi. Compared with MnZn soft ferrite, NiZn soft ferrite are used at higher frequencies <0.1GHz. and they also have high saturation induction levels. In addition, with the advanced performances of electronic devices it is of great importance to suppress interfering signals, NiZn ferrites with high impedance in covered frequency range can be used for interference suppression purposes where unwanted high frequency signals are blocked. The combination of the unique properties of graphene with new device developments and nanotechnology can achieve relevant improvements on the properties and main limitations of traditional RF electronics in terms of linearity, maximum frequency, and power dissipation. In this work, the influence of the grapheme nano-platelets inserted in the magnetic matrix on SEY is also studied [6-9].