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

Abstract Electron spin resonance (ESR) measurements in a La 7/8 Sr 1/8 MnO 3 single crystal are presented. Special attention is paid to the paramagnetic (PM) regime, where an anisotropic peak- to-peak linewidth is found. The angular variation for the static magnetic field , H 0 , in the (0 0 1), (0 1 0), and (1 1 0) planes 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, it is larger in the Jahn–Teller (JT) distorted O′ phase and decreases gradually with temperature. A small anisotropy is still present above T JT for H 0 in the (1 1 0) plane, suggesting the persistence of local JT distortions.