Nd 3+ crystal-field study of weakly doped Nd 1− x Ca x MnO 3

Abstract Nd3+ crystal-field excitations in Nd1−xCaxMnO3 (x=0.025, 0.05 and 0.1) single crystals are studied via infrared transmission as a function of temperature and external magnetic field. We report excitations associated with Nd3+ sites as detected in NdMnO3 and excitations due to Ca doping. The latter reveal phase separation between the usual A-type antiferromagnetic states and the insulating canted (ferromagnetic) spin states in the vicinity of doped Ca2+ ions. Both Nd3+ crystal-field levels could be described using calculated parameters for NdMnO3. Also, while oxygen stoichiometry and coherent Jahn–Teller distortions seem not to be affected by Ca doping, increased absorption bandwidths characterize the doped crystals.