Structural, magnetic, and electrical properties of La 1 x Nd x Mn 0.8 Cr 0.2 O 3 (xp0.3)

We have investigated the structural, magnetic, and electrical transport properties of a series of ABO3-type perovskite compounds, La1� xNdxMn0.8Cr0.2O3 (xp0.3). The parent compound LaMn0.8Cr0.2O3 is a ferromagnetic semiconductor with a Curie temperature Tc of 156 K. Upon Nd doping on La sites, the lattice parameters, unit cell volume, the B–O–B bond angle, and the B–O bond length are reduced. The Curie temperature decreases with increasing Nd content. However, Nd doping enhances the saturation magnetization at 5 K, which indicates that the Nd 3+ moments tend to be parallel to the Mn 3+ /Cr 3+ moments at low temperature. All the samples are semiconducting throughout the temperature range studied. The resistivity can be described by the adiabatic small polaron hoping model, with an apparent reduction of polaron activation energy (Ea) below Tc. In a 13 T high magnetic field, the resistivity remains semiconducting although Ea is suppressed. The effects of Nd doping in LaMn0.8Cr0.2O3 are discussed in terms of the smaller size and the high moment of Nd 3+ ions.