Influence of Mn-site doping on charge and orbital ordering in La 1 / 3 Ca 2 / 3 Mn 1 − y M y O 3 manganites ( M = Ni , Ga )

The influence of Ni and Ga doping on orbital and charge ordering (CO) in La1/3 Ca2/3 Mn1−y My O3 (M: Ni, Ga, and 0≤y≤0.1) has been investigated by combining magnetic and transport measurements with observation and analysis in transmission electron microscopy (TEM). Both types of doping cause a gradual decrease of TCO—the temperature of the charge ordering transition—while the temperature dependences of the magnetization and electric resistivity remain typical of the CO state. In the undoped parent sample, direct observations by TEM reveal the extended commensurate striped superstructure with q-vector 1/3a* over the whole temperature range