Influence of metal magnetic state and metal-insulator-semiconductor structure composition on magnetoimpedance effect caused by interface states

Abstract

This article presents the results of the study of metal/insulator/semiconductor (MIS) hybrid structures transport properties in alternating current (ac) mode. We prepared a series of samples with different layers of metal, insulator and semiconductor. Ferromagnetic Fe and non-magnetic Cu and Mn were chosen as metals, the insulators were SiO 2 and Al 2 O 3 , Si substrates of n-and p-type were used as semiconductors. Temperature dependence of real part of the impedance showed peculiar peaks below 40К for different combinations of metals, insulators and semiconductors. For all samples the effect of magnetic field on the transport properties was studied. At low temperatures, the magnetic field shifts peaks toward higher temperatures. Metal magnetic state doesn't significantly affect this phenomenon. Changing the type of the insulator and its thickness also didn't cause any significant effect. The effect was observed for samples with different composition. However, the type of conductivity of the substrate, as well as the type of metal, determines the value of magnetoimpedance (MI). The main role in the magnetoimpedance effect is played by recharging of energy states localized at insulator/semiconductor interface. This mechanism allows obtaining MI effect even in "nonmagnetic" MIS structures; MI can be either positive or negative, depending on temperature and frequency. We suggest that the observed ac magnetotransport phenomena could be used for creating magnetic field sensors, working on new principles.

Temperature Dependence Of Energy States And Band Gap Broadening

“…Temperature Dependence Of Energy States And Band Gap Broadening 54 By this, formula (1) of the ideal model is a step function. In work [2,3] ( ) E  as determining the lifetime of an electron which is strongly dependent on the energy E is represented in the form ( )…”

“…Modeling of the temperature dependence of the density of surface states for a wide energy range, which includes the allowed and forbidden bands of a semiconductor, it becomes possible to obtain more accurate information on the nature of localized states at the semiconductor - [2].…”

Modulation of the magnetoimpedance effect of ZnO:Ag/NiFe heterostructures by thermal annealing

“…The MI effect has been explored in a wide variety of samples [9][10][11] , giving rise to a broad range of remarkable results. Among the different geometries, planar heterostructures consisting of a bilayer with a magnetic material and a non-magnetic metal/semiconductor have been drawing considerable attention due to the perspective of application in spintronics 12,13 . One of the most paradigmatic materials in this field is Y3Fe5O12 (YIG), a ferrimagnetic insulator that, when capped by a non-magnetic metal with high spin-orbit coupling, enables the evaluation of pure spin-current effects in films with bilayer geometry 5,6 .…”