STRUCTURE DEPENDENCE OF THE FERROMAGNETIC TRANSITION-TEMPERATURE IN RHOMBOHEDRAL LA(1-X)A(X)MNO(3) (A=NA, K, RB, AND SR)

Structure analysis and measurement of resistivity under both isostatic pressure smaller than 1.1 GPa and magnetic field of 1 T were carried out for rhombohedral La(1-x)A(x)MnO(3) (A = Na, K, Rb, and Sr). A close relationship was confirmed to hold between T-c and the bond distance of Mn-O. The application of the isostatic pressure up to 1.1 GPa decreased the resistivity more than 60% below T-c but this effect was smaller above T-c. This pressure dependency was explained by the decrease in bond distance of Mn-O under pressure. Magnetic resistance for La0.87K0.06Mn0.97O3 was found to be - 10%/T, which is the same order of the previous reports for La(1-x)A(x)MnO(3) (A = Ca, Sr, Ba).