Anisotropic ESR linewidth and Jahn-Teller distortions in La7/8Sr1/8MnO3

Electron spin resonance (ESR) measurements in a La7/8Sr1/8MnO3 single cryst al are presented. Special attention is paid to the paramagnetic (PM) regime , where an anisotropic peak- to-peak linewidth is found. The angular variat ion for the static magnetic field, H-0, in the (001), (010), and (110) plan es indicates a tetragonal (D-4.) symmetry for the ESR spectrum, where the c direction is the four-fold axis. The anisotropy is strongly T dependent, i t is larger in the Jahn-Teller (JT) distorted O' phase and decreases gradua lly with temperature. A small anisotropy is still present above T-JT for H- 0 in the (110) plane, suggesting the persistence of local JT distortions. ( C) 2001 Elsevier Science B.V. All rights reserved.