Electronic phase transitions and magnetoresistance in a new bilayer manganate, Ca2.5Sr0.5GaMn2O8

Journal article

The crystal structure of the anion-deficient perovskite Ca2.5Sr0.5GaMn2O8 has been studied at 290 and 5 K by neutron diffraction (290 K; space group Pcm21, a = 5.4294(1), b = 11.3722(3), c = 5.2983(1) Å). The vacant oxide sites order to create a structure in which perovskite bilayers consisting of MnO6 octahedra are isolated from each other along [010] by a single layer of GaO4 tetrahedra. At 5 K the material is antiferromagnetic with an ordered magnetic moment of 3.09(1) μB per Mn cation. Magnetic susceptibility measurements suggest that short-range magnetic ordering within the bilayers occurs above 200 K, and muon spin relaxation data show that the transition to long-range magnetic order occurs between 150 and 125 K. The resistivity of Ca2.5Sr0.5GaMn2O8 decreases by an order of magnitude at 125 K, and ∼50% magnetoresistance is seen in a field of 80 kOe at 110 K.

Authors: Battle, P; Blundell, S; Santhosh, P; Rosseinsky, M; Steer, C

• Publication status: Published
• Journal: JOURNAL OF PHYSICS-CONDENSED MATTER
• Volume: 14
• Issue: 49
• Pages: 13569-13577
• Publication date: 2002-12-16
• DOI: 10.1088/0953-8984/14/49/312
• ISSN: 0953-8984
• Language: English