摘要:

High precision electrical resistivity (&rgr;) measurements are carried out on amorphous Fe80−xNixB20(x=20, 40, 50, and 60) alloys in the temperature range 5 to 750 K. All the samples show a minimum in resistivity (&rgr;min) and the temperature (Tmin), at which &rgr;minoccurs, lies in the temperature range 10–15 K. ForT<Tmin, &rgr; shows logarithmic temperature dependence and aboveTmin , &rgr; varies quadratically with temperature. Measurement of Curie (Tc) and crystallization (Tx) temperatures precedes Curie temperature and for other samplesTcvalue decreases with increasing Ni concentration. A detailed data analysis, carried out in the light of existing theories with emphasis to magnetic contribution to total resistivity in these alloys, is presented and compared with the earlier results.

ISSN:0094-243X    

DOI:10.1063/1.44709

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The magnetization study of Fe67Co18B14Si1has been carried out along with the structural relaxation effects, through Mossbauer spectroscopy and hysteresis studies. The variation in the hyperfine parameters up to an annealing at 573 K for two hours finds an explanation in terms of the changes in both the topological and chemical short range orders. Similarly the decrease in the coercivity has also been explained in terms of the annealing out of the flux pinning centers. However the samples annealed at 573 K and 473 K showed large coercivities which may be attributed to the presence of cobalt.

ISSN:0094-243X    

DOI:10.1063/1.44710

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Thermal expansion measurements are reported on Cr+0.18 at% Re alloy system near the Spin Density Wave transition atTN=318 K and incommensurate‐commensurate transition at 297 K. The nature of the transition atTNis deduced to be weakly first order and a large change in anharmonicity is observed which implies a considerable lattice softening belowTN.

ISSN:0094-243X    

DOI:10.1063/1.44711

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A review of the effect of diffusive motion of electrons on various low temperature magnetic, thermal, and transport properties is given.

ISSN:0094-243X    

DOI:10.1063/1.44712

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

We propose a model for memory within the framework of Neural Network which is akin to the realistic memory, in that it tends to forget upon learning more, and has both long‐term as well as short‐term memories. It has great advantage over the existing models proposed so far by Parisi and Gordon which have only short‐term and long‐term memories respectively. Our model resorts to learning within bounds like the previous two models, however, the essential difference lies in the reinitialization of the synaptic efficacy after it accumulates up to a preassigned value.

ISSN:0094-243X    

DOI:10.1063/1.44713

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The crystal structure of CaCO3is predominantly of aragonite form. The transformation of aragonite to calcite is found to start at 300 °C. The x‐ray reflection of aragonite found to be broader where as after the transformation the calcite reflections were sharper.

ISSN:0094-243X    

DOI:10.1063/1.44714

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A theory of phase transition in heme proteins has been developed which is applicable over a wide range of temperatures. Susceptibility data of [Fe(Bald)(NiIm)]CB. THF have also been analyzed.

ISSN:0094-243X    

DOI:10.1063/1.44715

出版商:AIP    

年代:1992

数据来源: AIP