Phenomenological analysis of phase coexistence in La0.75Ca0.25MnO3.

M. TOVAR; M.T. CAUSA; C.A. RAMOS; F. PRADO; D. LAURA CCAHUANA

PHYSICA B - CONDENSED MATTER

Elsevier B. V.

Año: 2006 vol. 384 p. 44 - 46

0921-4526

We found clear signatures of phase coexistence in the ESR and magnetization properties of La0.75Ca0.25MnO3. In our analysis, a mixed material, metallic and insulator, is described in terms of a free-energy, function of the magnetization of the two phases and the metallic fraction. When the Jahn–Teller interaction is considered, the order parameters become coupled and we found different possibilities: (a) a discontinuous change from PM-I to FM-M, (b) a continuous PM-I to FM-I transition followed by discontinuous FM-I to FM-M and (c) a temperature region of coexistence of the high temperature PM-I phase with the low-temperature FM-M phase.0.75Ca0.25MnO3. In our analysis, a mixed material, metallic and insulator, is described in terms of a free-energy, function of the magnetization of the two phases and the metallic fraction. When the Jahn–Teller interaction is considered, the order parameters become coupled and we found different possibilities: (a) a discontinuous change from PM-I to FM-M, (b) a continuous PM-I to FM-I transition followed by discontinuous FM-I to FM-M and (c) a temperature region of coexistence of the high temperature PM-I phase with the low-temperature FM-M phase.