•Critical exponents have been evaluated for Eu0.5Sr0.5CoO3.•Eu0.5Sr0.5CoO3 belongs to the mean-field class with long-range interaction.•Itinerant ferromagnetism dominates in Eu0.5Sr0.5CoO3.The critical behaviors of ferromagnet Eu0.5Sr0.5CoO3 around TC = 140.5 K have been comprehensively investigated by analyzing a series of isothermal magnetization M(H) curves. Both modified Arrott plot and Kouvel–Fisher methods give nearly the same critical exponents, which scale nicely the M(H) curves into two different branches below and above TC. The exponents γ = 1.044 and δ = 3.06 demonstrate the relevance of mean-field characters for this material. The conclusion of mean-field behavior proves a dominant itinerant ferromagnetism (FM) due to a long range exchange interaction in the system. Meanwhile, by using Rhodes-Wohlfarth’s criterion [P. Rhodes, E.P. Wohlfarth, Proc. R. Soc. Lond. A 273 (1963) 247], it is further confirmed that the itinerant FM dominates in the system.

In this paper, we investigated the electrical and magnetic properties of electron-doped manganite Y 0.4Ca0.6MnO3 with a relatively small average cationic radius 〈rA〉〈rA〉. The small 〈rA〉〈rA〉 of the present system results in a short-range antiferromagnetic charge-ordering (AFM-CO) state in the manganite. With the decrease of temperature, a ferromagnetic super-exchange interaction begins to establish itself between the remaining disordered Mn ions after the formation of the short-range CO state. Then, a reentrant cluster-glass state originates from the frustration between the FM order in the clusters and the AFM interactions present in the background matrix.

The magnetic properties of Y 0.35Ln0.05Ca0.6MnO3 (Ln = La, Pr, Nd, Sm, Gd, Dy) have been investigated thoroughly. The small average cationic radius 〈rA〉〈rA〉 of the present system results in a short-range antiferromagnetic charge-ordering (AFM-CO) state in the manganites. With the decrease of temperature, a super-exchange interaction begins to establish itself between the remaining disordered Mn ions after the formation of the short-range CO state. Then, the reentrant cluster-glass state originates from the frustration between the FM order in the clusters and the AFM interactions present in the background matrix. However, the large magnetic moments of Gd3+ and Dy3+ ions apply an internal magnetic field on the Mn3+ and Mn4+ ions, which results in the suppression of the cluster-glass state.

The magnetic properties of Nd0.6Ln0.1Sr0.3MnO3 compositions (Ln = La, Pr, Gd, Dy) have been investigated thoroughly. The effect of 〈rA〉〈rA〉 is considered to be profound on the PM–FM phase transition in the manganites. The experiment results indicate that TCTC decreases with Ln changing from La to Gd due to the decreases of 〈rA〉〈rA〉. The abnormal increase of TCTC in Dy-composition with the smallest 〈rA〉〈rA〉 and largest σ2σ2 is attributed to the large magnetic moment of Dy3+ ions. The rapid increase of magnetization below 30 K indicates directly the magnetic ordering of rare earth ions at A-site.

The electrical and magnetic properties of highly doped manganite Gd0.4Ca0.6MnO3 with a relatively small 〈rA〉 have been investigated thoroughly. Through the M–TM–T, M–HM–H, and ESR measurements it is found that the magnetization in M–TM–T curve originates from the paramagnetic contribution of disordered Mn ions at B-site and Gd3+ ions at A-site. The peculiar behavior of M–TM–T curve below TCO originates from the remaining spin disordered Mn ions after the formation of charge-ordering phase in the manganite, and the AFM charge-ordering state is supposed to be a local short-range ordering state.

The structural, magnetic, and transport properties of the polycrystalline-doped systems Nd0.7Sr0.3Mn1−xGaxO3 (0≤x≤0.200≤x≤0.20) were investigated. For the parent and low-doped samples (0≤x≤0.110≤x≤0.11), they show a long-range ferromagnetic state below TCTC and the Griffiths singularity above TCTC. When xx further exceeds 0.12, a transition from the metal ferromagnetic to the insulating cluster-spin-glass state as a function of Ga doping takes places at low temperatures. x=0.12x=0.12 is just a critical point xcxc transforming from the Griffiths singularity to the cluster-spin-glass state.

The effect of Mn substitution for Cu in mixed-valence Mn doped La1.85−(4/3)xSr0.15+(4/3)xCu1−xMnxO4 (x=0.06) has been investigated by electric resistivity, magnetization and electron spin resonance experiments. Coexistence of superconductivity and ferromagnetism was observed.

The magnetic properties of Y 0.35Ln0.05Ca0.6MnO3 (Ln = La, Pr, Nd, Sm, Gd, Dy) have been investigated thoroughly. The small average cationic radius 〈rA〉 of the present system results in a short-range antiferromagnetic charge-ordering (AFM-CO) state in the manganites. With the decrease of temperature, a super-exchange interaction begins to establish itself between the remaining disordered Mn ions after the formation of the short-range CO state. Then, the reentrant cluster-glass state originates from the frustration between the FM order in the clusters and the AFM interactions present in the background matrix. However, the large magnetic moments of Gd3+ and Dy3+ ions apply an internal magnetic field on the Mn3+ and Mn4+ ions, which results in the suppression of the cluster-glass state.