Magnetoelastic investigations at Pr1-xCaxMnO3(x=0.35,0.5) manganites

The magnetoelastic properties of the Pr1-xCaxMnO3 manganites were investigated for samples with x=0.35 and 0.5 by magnetostriction experiments using a capacitive miniature dilatometer at high magnetic fields. The forced magnetostriction, measured at several temperatures between 2 and 240 K and at fields up to 23 T at the Grenoble high-field laboratory, is characterized by a lattice contraction of about 10-3 at the transition from the charged ordered insulating into the ferromagnetic metallic state. The effect is highly hysteretic. In contrast, the antiferromagnetic ordering process does not change the lattice remarkably. Our findings agree well with the results of sound velocity experiments and confirm the (H,T) phase diagram. The strong correlation effects between the lattice and the electronic system indicate the importance of the magnetoelastic coupling in these colossal magnetoresistance (CMR) compounds.