Zener relaxation in manganites?

HORACIO R. SALVA; ADA A. GHILARDUCCI; SILVIA S. SEIRO; GABRIELA LEYVA; RODOLFO SÁNCHEZ

PHYSICA B - CONDENSED MATTER

Elsevier

Lugar: Amsterdam; Año: 2006 vol. 384 p. 62 - 64

0921-4526

We conducted internal friction (IF) and elastic modulus measurements on several manganites in the temperature range 100–500 K. The La1−xCaxMnO3 series, with x=0, 0.1, 0.2, 0.33 and 1, was studied showing the magnetic phase transitions and two additional IF peaks around 320 and 400 K, respectively. Both, peaks associated to relaxations, present activation enthalpies of 2–3 and 3–6 eV, whose intensity depends on x. In this work we associate the 400 K IF peak to a Zener relaxation of the cations that occupied the same crystallographic site. We believe that the 320 K IF peak is due to different crystalline states of the samples.