ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Application of the sputtering technique to (Al2O3)xBi100−x and (AIN)x Bi100−x (x = 0 to 100%) has been found to result in the formation of a duplex material consisting of hexagonal bismuth particles dispersed finely and homogeneously in amorphous AlxOy and AlxNy matrices. The particle size and interparticle distance of the bismuth phase were about 5 to 140nm and 5 to 35 nm. The duplex alloys have high electrical resistivities ranging from 1.82 × 103 to 3.16 × 105 μΩcm combined with a negative temperature-dependent resistivity of 148 to 342% of ϱ273. Furthermore, all the Al-O-Bi and Al-N-Bi alloys have been found to exhibit a positive magnetoresistive change and the maximum value, Δϱ(H), at 4.2 K and 7.5T reaches 5.85 × 104 μΩ cm for (Al-O)65.7Bi34.3 and 1.99 × 105 μΩcm for (Al-N)69.7 Bi30.3. The large magnetoresistivities are probably due to the unique sputtered structure consisting of metallic bismuth particles with a long mean free path of electrons embedded finely and homogeneously in amorphous AlxOy or AlxNy matrix, resulting in the large difference of the relaxation times (different mobilities) of electron carriers. It has thus been demonstrated that the oxide- or nitride-based composite materials exhibiting large magnetoresistivities, which cannot be achieved in metallic composite materials, are obtained by sputtering simultaneously Al2O3 or AIN and bismuth which is immiscible to aluminium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01111887
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