Determination of the baric coefficient using a double ac method - art. no. 073904

Abstract

An apparatus has been designed which measures the baric coefficient gamma, defined as the relative change of a resistance under pressure: R=R-0(1+gamma p), using a double ac method, the pressure modulation of the resistance being obtained via compressional sound waves. First results on manganites RE(1-x)A(x)MnO(3) are obtained and compared with the pressure derivatives of R(p,T) as obtained with static methods. Good agreement was obtained at larger superimposed static pressure P-st, however, extra results are obtained in the limit P-st -> 0 and in the case of a percolation of phase separated volumes. (c) 2005 American Institute of Physics.