Phase transitions in Sm_1–<i>x</i>Sr_<i>x</i>MnO₃ single crystals (0 ≤ <i>x</i> ≤ 0.8)

Abstract

Abstract Magnetic and electrical properties of Sm 1– x Sr x MnO 3 (0 ≤ x ≤ 0.8) single crystals have been studied and the T – x phase diagram has been revised. The compensation points of spontaneous weak ferromagnetic moment have been observed for pure SmMnO 3 and for low doped compositions (0 ≤ x &lt; 0.05). For 0.4 ≤ x ≤ 0.475 the ferromagnetic ordering occurs as a first‐order phase transition. It is shown that in a magnetic field the temperature of this transition increases and the transition becomes broader, which results in the appearance of a critical point ( T cr ∼ 193 K, H cr ∼ 68 kOe for x = 0.45). Another transition, accompanied by a reduction of magnetization and noticeable anisotropy of magnetization curves, has been observed at low temperature T s ∼ 40 K. Below the Neel temperature, a pure antiferromagnetic state without spontaneous magnetization has been observed for 0.5 ≤ x ≤ 0.575, while for 0.6 ≤ x ≤ 0.675 an additional low‐temperature transition to a new phase with a non‐zero weak‐ferromagnetic moment has been found.