ESR study of strain effect on phase separation in Pr<inf>0.7</inf>(Ca<inf>0.6</inf>Sr<inf>0.4</inf>)<inf>0.3</inf>MnO<inf>3</inf> Thin Films

Abstract

The rare-earth manganites R 1−x A x MnO 3 have stimulated considerable scientific and technological interest in recent years due to their exotic electronic and magnetic properties [1]The fascinating physics of these materials is driven by a close coupling between charge, spin, lattice and orbital degree of freedom, which has commonly resulted in phase separation between charge/orbital order (COO) and ferromagnetic (FM) metallic phase. One family of these manganites is Pr 1−x Ca x MnO 3 with 0.3≤ × ≤0.75 which has a narrow one-electron bandwidth of e band (W) and exhibits an insulator-metal transition (IMT) [2]. With the doping level unchanged, the substitution of Sr2+ for Ca2+ would modify the local structural parameters such as Mn-O-Mn bond angel and bond length, hence widens the W. As a result, an intense competition between the COO phase and FM metallic phase upon Sr doping is expected. Strain or pressure would provide a very efficient means of modulating the magnetic and electric properties of these materials. Here we investigate the strain effect on phase separation in Pr 0.7 (Ca 0.6 Sr 0.4 ) 0.3 MnO 3 (PCSMO) system with electron spin resonance (ESR). ESR is an efficacious method for the study of magnetic interaction and phase separation in these manganites due to its extreme sensitivity to spin correlation and local environment [3].