Anisotropy of Resistance and Magnetoresistance of Pr_0.5Nd_0.5BaMn₂O₆ Single Crystal with Partial A-Site Ordering

The features of the charge subsystem of the Pr_0.5Nd_0.5BaMn₂O₆ single crystal with partial A-site ordering are investigated. The manganite is a mixture of a phase with a tetragonal structure (43%) with a high degree of A-site ordering and a disordered phase with a cubic structure (57%). Anisotropy of the optical properties and electrical resistance in the crystallographic ab plane and along the c axis was found. The anisotropy manifests itself as a metal–insulator transition near T≈T_C = 150 K in the ab plane and a semiconductor character of the resistance along c above and below T_C. The magnetoresistance effect was revealed, which in a field of 1 T reaches 65% in the ab plane and 45% along the c axis near T_C and about 40% at low temperatures.