Itinerant ferromagnetism to insulating spin glass in SrRu1−xCuxO3 (0≤x≤0.3)

Abstract

The ferromagnetic metallic oxide, SrRuO3 (TC ∼ 165 K) undergoes structural, magnetic and metal–insulator transitions upon substitution of Cu at the Ru-site. For x = 0.2 in SrRu1−xCuxO3, the structure becomes a tetragonal with the space group I4/mcm and there is a signature of both ferromagnetic (TC = 65 K) and antiferromagnetic (TN = 32 K) ordering due to possible magnetic phase separation. The antiferromagnetism arises due to short range ordering of Cu- and Ru-moments. Jahn–Teller distortion of (Ru,Cu)–O6 octahedra indicates that the copper ions are in 2+ oxidation state with electronic configuration. For x ≥ 0.1, narrowing of Ru-4d bandwidth by the substitution of Cu ions results in semiconducting behavior. For x = 0.3, the ac and dc susceptibility measurements indicate a spin glass behavior. The origin of spin glass behavior has been attributed to competing ferromagnetic and antiferromagnetic interactions.