We have studied magnetic, elastic, and transport properties of Eu_0.55Sr_0.45MnO₃ (1) and Sm_0.55Sr_0.45MnO₃ (2) ceramic. For (1) the resistivity ρ shows an insulating behaviour even at 4.2 K. Near T_C a break on the ρ(T) dependence and on the temperature dependence of linear thermal expansion was observed for (1) and the sharp maximum on the ρ(T) dependence and sharp volume change ΔV/V ~ 0.1% was observed for (2). For (1) in the wide temperature region from 4.2 K to T >> T_C the sharp jump of magnetization σ, volume magnetostriction ω, and ρ takes place at H_C1 < H < H_C2, i.e. under magnetic field action the phase transition from insulating AFM-like state to metallic FM-like state occurs. σ(H) curves are not saturated at H > H_C2 up to 80 kOe. The maximal value of σ is less than one corresponding FM ordering of Mn³⁺ and Mn⁴⁺ ions, namely 70% from latter at 4.2 K under 80 kOe. The metallic FM-like state was unchanged after field removing. Such behaviour is observed within temperature interval from 4.2 to 50 K. At temperatures from 50 to 120 K the jump of σ, ω, and ρ is maintained, but shape of σ(H), ω(H), and ρ(H) curves is changed and sample return in original state after field removing. The value of H_C decreases with increasing T within first and increases within second interval. For (2) sharp jump of σ, ω, and ρ takes place at H_C1 < H < H_C2 at T > T_C only, and their saturation is achieved at H > H_C2. For (1) MR is positive at H < H_C1 and reaches of 6% value, at H > H_C1 MR becomes negative and reaches of 10⁵ %. ω is negative and giant for both compounds and is observed from 4.2 K to T >> T_C for (1) and in the T_C region only for (2). We consider that differnt types of inhomogeneous magnetic state are realized in our compounds and reason of CMR and giant ω is the increase of FM phase volume under field action.

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1. Giant volume magnetostriction in manganites and its connection with colossal magnetoresistance