title: Competition between ferromagnetism and antiferromagnetism: origin of large magnetoresistance in polycrystalline SrRu(1-x)Mn(x)O(3) (0≤x≤1).
abstract: Polycrystalline SrRu(1-x)Mn(x)O(3) (0≤x≤1) perovskite oxides have been prepared by a conventional solid-state reaction technique. Magnetic and magnetotransport properties are measured using a superconducting quantum interference device (SQUID, Quantum Design MPMS) over a temperature range of 4-300 K. The substitution of Mn ions for Ru drives the system from a ferromagnetic state, SrRuO(3), to an antiferromagnetic state, SrMnO(3), which is basically similar to observations in single-crystal SrRu(1-x)Mn(x)O(3) (Cao et al 2005 Phys. Rev. B 71 035104). However, the measurement of dc magnetization and ac susceptibility indicates that magnetic phase transition with x is more complicated and pronounced than those in single crystals. The phase transition process as temperature is reduced covers paramagnetism-antiferromagnetism (PM-AFM), paramagnetism-ferromagnetism (PM-FM) and ferromagnetism-cluster glass-spin glass (FM/CG/SG) etc. In particular, we observe a large low-temperature magnetoresistance (MR) of -41% for the sample x = 0.55, which is the largest MR measured in Mn-doped SrRuO(3). The experiment has verified that the large MR stems predominantly from a unique spin glass state in the polycrystalline alloy. These results substantiate that Ru-based oxides doped with 3d/4d transition metals have the potential for use in spintronics devices due to their adjustable phase transition, depending upon the level and nature of 3d/4d ion doping.
authors.affiliation: Department of Physics and Jiangsu Key Laboratory of Thin Films, Suzhou University, Suzhou 215006, People's Republic of China. Laboratory of Solid State Microstructures, Nanjing University, Nanjing 218008, People's Republic of China.
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Zhang
authors.forename: Yajie
authors.initials: Y
authors.lastname: Chen
authors.forename: Zhen-Ya
authors.initials: ZY
authors.lastname: Li
authors.forename: Carmine
authors.initials: C
authors.lastname: Vittoria
authors.forename: Vincent G
authors.initials: VG
authors.lastname: Harris