Reduction of critical field for magnetic and orbital-ordering phase transition in impurity-substituted Nd0.45Sr0.55MnO3 crystal

We have investigated the Mn-site substitution effect in Nd0.45Sr0.55MnO3 single crystal, which has an A-type layered antiferromagnetic (A-AFM) phase with the 3\documentclass[12pt]{minimal}\begin{document}$d_x^2-y^2$\end{document}dx2−y2-type orbital-order. Substitution of Fe or Ga for Mn-site suppresses both the A-AFM order and competing ferromagnetic (FM) correlation, whereas Cr substitution suppresses only the A-AFM order but reactivates the underlying FM correlation via double-exchange mechanism along the AFM coupled c-direction. In Nd0.45Sr0.55Mn0.95Cr0.05O3, the A-AFM state with the orbital-order is changed into the orbital-disordered three-dimensional FM metallic state by applying magnetic field of μ0H = 12 T, which is much smaller than that of the parent compound Nd0.45Sr0.55MnO3.