Chemical pressure effects on Tm1-R Mn0.3Co0.7O3 due to element substitution at A-site

To clarify the chemical pressure effects on TmMn _0.3Co _0.7O ₃ due to element substitution at an A -site, the crystal structure and magnetic properties of Tm _{1- y}R _yMn _0.3Co _0.7O ₃ (R = Y and Lu) were investigated. All the prepared samples possessed a perovskite-type orthorhombic structure with the Pnma space group, and the unit-cell volume V increased with the average radius of A-site ions 〈 r R 〉 . From the effective magnetic moment P _eff and M− H measurements, it was found that the electronic states of the ions in the samples were Tm ³⁺, Mn ⁴⁺, Co ²⁺(high-spin state, S = 3/2), and Co ³⁺(low-spin state, S = 0). The physical parameters including the canted antiferromagnetic transition temperature T _c increased with V. The field-cooled magnetization M _FC below 30 K could be explained by the antiferromagnetic interaction between the paramagnetic Tm and the 3 d metal sublattices. Since T _c and the fitting parameter of this two-sublattice model increased with V, these changes were considered to be attributed to the chemical pressure generated by element substitution at the A-site.