Piezoresistivity Coefficients in Manganin

Abstract

The piezoresistivity coefficients for Manganin have been determined from the static and shock pressure dependence of the resistance. An analysis is presented which relates the piezoresistivity coefficients to resistance changes under conditions of one-, two-, and three-dimensional dynamic strains and hydrostatic strain. This analysis shows that the piezoresistance values depend on the mode of strain and reconciles the different piezoresistance values, reported in the literature, to a unique but pressure dependent piezoresistivity coefficient. The dynamic piezoresistance predicted from static piezoresistance pressure data and mechanical data using this analysis is in good agreement with the observed values. The observed piezoresistivity which is of opposite sign to that predicted from the pressure dependence of the lattice scattering, is discussed in terms of an s-d scattering model for Manganin and other alloys of copper containing elements with unfilled 3d electron states. This model suggests that several of these alloys have a higher coefficient than Manganin, and may explain the large positive piezoresistance reported in the literature for calcium, strontium, and barium.