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Bias Exponent of Resistance Noise as a Probe for Disordered Systems
Author(s) -
Dey Animesh Kr.,
Nandi Upendranath,
Talukdar Deep,
Chakrabarty Rajkumar,
Bardhan Kamal Kumar
Publication year - 2018
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201700664
Subject(s) - condensed matter physics , exponent , spectral density , noise (video) , ohmic contact , manganite , physics , gaussian , materials science , electrical resistivity and conductivity , mathematics , quantum mechanics , statistics , philosophy , linguistics , artificial intelligence , computer science , image (mathematics) , electrode , ferromagnetism
The power spectral density S v ( f ) of voltage fluctuations in the Ohmic regime of a system varies with voltage V as S v ( f ) ≈ V β where β is the bias exponent. The equilibrium resistance fluctuation in a homogeneous system provides β = 2 but in disordered systems, we show that β strongly depends on quenched disorder and temperature and is less than 2 in the Ohmic region. At a fixed temperature, β remains nearly equal to 2 at low disorder and decreases from 2 to 1 with the increase in disorder. Interestingly, similar variation in β is observed with the change in temperature from high to low at a fixed quenched disorder. These two cases favor weak localization in the limit of high disorder or low temperature. Experimental results on manganite compounds indicate that the bias exponent β could be used as a sensible nondestructive parameter to identify the existence of a phase transition evolved during the course of investigation. Remarkable correlations between the electrical transport and the power spectral density S v ( f ) are observed and explained with the help of inhomogeneous distribution of currents. The results are also supported by the non‐Gaussian nature of the second spectrum of 1/ f noise at different temperatures.