Magnetoresistance effect

Special applications, such as in high-magnetic fields, require special thermometers. The carbon-glass and strontium-titinate resistance thermometers have the least magnetoresistance effects. 

Figure 6.75 Variation in resistivity of two ironchromium superlattices of various layer thicknesses due to magnetoresistive effect. Reprinted, by permission, from P. Ball, Made to Measure, p. 77. Copyright 1997 by Princeton University Press.

The discovery in 1986 of high-temperature superconductivity in ceramic cuprates of perovskite structure started a period of very intensive research of transition metal oxides. Soon afterwards, in 1993, the colossal magnetoresistance effect was discovered in manganite perovskites, again leading to an increasing research activity in the field of magnetic oxides. It is... 

Figure 2. Asymmetric spin dependent scattering at CoFe/Cu and NiFe/Cu interfaces leads to the giant magnetoresistance effect observed in a (CoFe/Cu/NiFe/Cu)x2o multilayer stack (S. Cardoso, INESC MN).

A Bruker IFS 113 Fourier transform spectrometer was employed to study reflectance spectra of multilayer structures at 300 K in the mid-IR range from 2.5 to 25 pm. The IR radiation was focused onto the sample placed in the electromagnet gap. The magnetoreflectance was determined by analogy with the magnetoresistive effect A/o// = p H=0), and AR/R= R(H)-... 

Inset of Fig. 1 shows the high correlation between the electrical measured GMR (TMR) and the optically measured MRE for CoFe/Cu and CoFe/AljOs multilayers. The differences in the nonmagnetic layer (Cu or AI2O3) lead to different values of the magnetoresistive effect. 

Enhanced magnetoresistive effect, called giant magnetoresistance (GMR) effect, was observed in magnetic layered structures consisting of magnetic/nonmagnetic metal multilayers [131,132], First, GMR multilayers were produced by vacuum deposition... 

Endo, M. Hishiyama, Y. Koyama, T. Magnetoresistance effect in graphitizing carbon fibres prepared by benzene decomposition. J. Phys. D Appl. Phys. 1982, 15, 353-363. 

Active sensors require an external power supply for operation. This is the 5 or 12 V system of the ECU. The main technologies are the complementary metal-oxide semiconductor Hall-effect transducers (CMOS-Hall) or AMR (anisotropic magnetoresistive effect) plus silicon amplification [3],... 

Active WSS work on galvanomagnetic principles like the Hall or MR (magnetoresistive) effect. The sensor needs an external power supply. Compared with the passive WSS, the signal (amplitude) of active WSS depends not on the speed. The output level is constant. 

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