Fragile magnetic ground state in half-doped LaSr2Mn2O7

• Published in: Physical review letters Vol. 107; no. 3; p. 037206
• Main Authors: Lee, J-S, Kao, C-C, Nelson, C S, Jang, H, Ko, K-T, Kim, S B, Choi, Y J, Cheong, S-W, Smadici, S, Abbamonte, P, Park, J-H
• Format: Journal Article
• Language: English
• Published: United States 15.07.2011
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.107.037206

We investigated the orbital and antiferromagnetic ordering behaviors of the half-doped bilayer manganite La(2-2x)Sr(1+2x)Mn2O7 (x ≃ 0.5) by using Mn L(2,3)-edge resonant soft x-ray scattering. Resonant soft x-ray scattering reveals the CE-type orbital order below T(oo) ≃ 220  K, which shows partial melting behavior below T(m) ≃ 165  K. We also found coexistence CE- and A-type antiferromagnetic orders. Both orders involve the CE-type orbital order with nearly the same orbital character and are coupled with each other. These results manifest that the ground state with the CE-type antiferromagnetic order is easily susceptible to destabilization into the A-type one even with a small fluctuation of the doping level, as suggested by the extremely narrow magnetic phase boundaries at x ≃ 0.5±0.005.