Multilayer ferrites

FIGURE 6.1.18 Printing method for multilayer ferrite chip inductor. 

FIGURE 6.1.19 Schematic models of representative multilayer ferrite chip components (Multilayer chip inductor, Multilayer LC hlter, and Multilayer hybrid component). 

Materials for MO Media. The materials classes best suited for MO media are RE-TM alloys, Co/Pt multilayers, and ferrites. The quality of disks is mainly characterised by the signal-to-noise ratio (SNR). 

It has also been suggested that flow might occur at lower stresses than those predicted above by movement of material within the individual layers (Chu and Barnett, 1995). This has been observed in pearlitic structures made up of alternating layers of ferrite and cementite, and observations in other multilayer systems suggest that that deformation might occur in this way (Gil-Sevillano, 1979). Two cases have been identified the first where only the movement of a pre-existing dislocation loop is required, the second where the activation of a dislocation source within the layer is needed. Gil-Sevillano (1979) showed that the extra stress, Atm, required to move a dislocation half-loop in a layer of width 1 is... 

Fig. 9.17 Range of soft ferrite components (i) TV scanning yoke (components kindly supplied by Philips Components Ltd.) (ii) UR core and TV line output transformer (iii) E core for switched mode power supply (iv) wide band transformer core (v) core giving good magnetic shielding (vi) high Q (adjustable) filter core (cf. Fig. 9.48) (vii) precision ferrite antenna for transponder (viii) multilayer EMI suppressors (ix) toroids for laser and radar pulse applications (x) typical EMI shields for cables, ((ii)—(x) Courtesy of Ferroxcube UK .)...

As concerns the piezoelectric layer, the first choice often goes to lead zirconate titanate (PZT) because of its outstanding piezoelectric, pyroelectric and ferroelectric properties. Nickel ferrite (NF) is not widely employed for the synthesis of the multilayered composites owing to a strong reduction of its magnetization in the lower grain size limit. However, a very thin NF layer can help to attain entirely different properties and, hence, this material has been chosen as a sandwiched layer in the present work. 

Abe, M., Itoh, T., Tamaura, Y. Gomi, M. (1988). Ferrite-organic multilayer film for microwave monolithic integrated circuits prepared by ferrite plating based on the spray-spin-coating method. Journal of Applied Physics, 63,3774-6. 

In this chapter, using samples of mainly three types of magnetic materials, namely, nanosized powders of ferrites, mechanically alloyed/milled Fe-Cr-AI intermetallics, and a Fe-AI multilayer system, it has been demonstrated how Mossbauer spectroscopy is a powerful tool to understand the bulk magnetic properties in such nanosized systems. This is mainly because of the extreme sensitivity of the Mossbauer probe atom to short-range effects that get modified on a... 

Ceramic and ferrite components such as multilayer ceramic capacitors, chip resistors, and chip inductors are generally terminated with a fired-on silver or silver palladium paste. Because silver dissolves easily into molten Sn-Pb solder, a Ni/Sn or Ni/Au overplate is recommended. 

Figure 2-39. Schematic diagram of the development of sulfide multilayers on ferritic steels (Schulte et al., 1998).

Similar studies have been reported by Ampomrat and Was on ferritic-martensitic alloys (T91, HCM12A, HT-9), Chen et al. on oxide dispersion strengthened 9Cr ferritic steel (9Cr ODS), and by Motta et al., also on 9Cr ODS steel. The findings of these studies are all broadly similar, where measmed, the oxidation follows a parabohc rate law and the oxide layer exhibits a bilayer (or, sometimes, a multilayer) structure comprising a chromirnn-iich spinel inner (barrier) layer and a porous, outer layer of magnetite. The proposed oxidation mechanisms are essentially the same as that articulated by Was et al." ... 

Penchal Reddy M, Madhuri W, Balakrishnaiah G, Ramamanohar Reddy N, Siva Kumar KV, Murthy VRK, Ramakrishna Reddy, R. Microwave sintering of iron deficient Ni-Cu-Zn ferrites for multilayer chip inductors. Current Applied Physics 2011 11 191-8. 

Magnetic nanoparticles showing Faraday rotation effect, and/or Kerr effect can be of interest in the fabrication of switches and devices. Size dependant transmittance and Faraday rotation have been found in maghemite ferrofluids and ferrite films." Multilayered assemblies of yttrium garnet nanoparticles show magnetization-induced second harmonic generation (Kerr effect)." In metal/PMMA nanocomposites, the main absorption band narrows and additional peaks appear when decreasing the particle size." ... 

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