Phonon spectra of cobaltite/manganites in strong magnetic fields

Far-infrared spectroscopy has been employed to determine phonon modes in the cobaltite/manganites A(Co1/2Mn1/2)O3, where A is a lanthanide, in magnetic fields up to 17.5 T. The phonon energies in the compounds with A=La,Nd or Ho show little change with applied magnetic field. In contrast, with A=Yb, all the phonon modes exhibit a splitting when a magnetic field is applied. It is thought that this field dependence of the phonon energies is related to the metamagnetism of Yb(Co1/2Mn1/2)O3