Effects of substitution at the manganese site in RE(Ni,Mn)O 3 perovskites (RE=Y, Eu)

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 104; no. 3; pp. 126 - 130
• Main Authors: Peña, O., Bahout, M., Ma, Y., Guizouarn, T., Gutiérrez, D., Durán, P., Moure, C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2003
• Subjects: Field-dependent magnetic properties; Manganese perovskites; Phase transitions; Spin-glasses; Substitution effects; Field-dependent magnetic properties; Spin-glasses; Phase transitions; Manganese perovskites; Substitution effects
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/S0921-5107(03)00184-3

The magnetically ordered states of the YNi x Mn 1− x O 3 and EuNi x Mn 1− x O 3 solid solutions (0.0≤ x≤0.50) have been studied at different temperatures and magnetic fields. The magnetization as a function of temperature M( T) shows features due to canted-antiferromagnetism ( x=0.25 and 0.33) and ferromagnetism ( x=0.50), while YNi 0.20Mn 0.80O 3 presents a spin-glass behavior. A large field-dependence of the susceptibility maximum at T max is found in the nickel-poor region, except for the spin-glass compound, for which T max stays constant at T SG∼20 K. For the nickel-rich samples the paramagnetic-to-ferromagnetic transition at T c is field-independent, with T c∼80 and 150 K, for YNi 0.50Mn 0.50O 3 and EuNi 0.50Mn 0.50O 3, respectively. The coercive field H coerc and the high-field data obtained from magnetization loops M( H) show a well-defined frontier at x= x crit=1/3, between canted-antiferromagnetism ( x≤ x crit) and full ferromagnetism ( x> x crit). This critical value corresponds to equal amounts of Mn 3+ and Mn 4+, leading to a maximum number of pairs Mn 3+/Mn 4+ and an optimum in the double-exchange interactions.