Disappearance of static magnetic order and evolution of spin fluctuations in Fe_1+δSe_xTe_1-x

Journal Article · Wed Sep 29 00:00:00 EDT 2010 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.82.104525· OSTI ID:1065171

Xu, Zhijun ^[1]; Wen, Jinsheng ^[2]; Xu, Guangyong ^[3]; Jie, Qing ^[3]; Lin, Zhiwei ^[3]; Li, Qiang ^[3]; Chi, Songxue ^[4]; Singh, D. K. ^[4]; Gu, Genda ^[3]; Tranquada, John M. ^[3]

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1. Brookhaven National Lab. (BNL), Upton, NY (United States); City College of New York, NY (United States)
2. Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., Stony Brook, NY (United States)
3. Brookhaven National Lab. (BNL), Upton, NY (United States)
4. National Inst. of Standards and Technology, Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States)

We report neutron-scattering studies on static magnetic orders and spin excitations in the Fe-based chalcogenide system Fev Se_1+δ Te_1-x with different Fe and Se compositions. Short-range static magnetic order with an in-plane wave vector near the (0.5,0) (using the two-Fe unit cell), together with strong low-energy magnetic excitations is found in all nonsuperconducting samples for Se doping up to 45%. When the static order disappears and bulk superconductivity emerges, the spectral weight of the magnetic excitations shifts to the region of reciprocal space near the in-plane wave vector (0.5, 0.5), corresponding to “collinear” spin correlations. Our results suggest that there is a strong correlation between superconductivity and the character of the magnetic order/fluctuations in this system. Excess Fe appears to be important for stabilizing the magnetic order that competes with superconductivity.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Center for Emergent Superconductivity (CES)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1065171
• Journal Information: Physical Review B, Vol. 82; Related Information: CES partners with Brookhaven National Laboratory (BNL); Argonne National Laboratory; University of Illinois, Urbana-Champaign; Los Alamos National Laboratory
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
phonons
thermal conductivity
energy storage (including batteries and capacitors)
superconductivity
defects
spin dynamics