Magnetic orders tuned by Cu substitution in Fe1.1 zCuzTe

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.86.024401· OSTI ID:1081932

Wen, Jinsheng ^[1]; Xu, Zhijun ^[2]; Xu, Guangyong ^[2]; Lumsden, Mark D ^[3]; Valdivia, P. N. ^[1]; Bourret-Courchesne, E. D. ^[4]; Gu, Genda ^[2]; Lee, Dunghai ^[5]; Tranquada, John M. ^[2]; Birgeneau, R. J. ^[1]

---

1. University of California, Berkeley
2. Brookhaven National Laboratory (BNL)
3. ORNL
4. Lawrence Berkeley National Laboratory (LBNL)
5. University of California, Berkeley & LBNL

We study the effects of Cu substitution in Fe1.1Te, the non-superconducting parent compound of the iron-based superconductor, Fe1+yTe1 xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at 60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.48, 0, 0.5), and correlation length of 12 A along the a axis and 9 A along the c axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first order transition to a longrange almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has large effects on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.

• Research Organization: Oak Ridge National Laboratory (ORNL); High Flux Isotope Reactor
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1081932
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 2 Vol. 86; ISSN 1098-0121
• Country of Publication: United States
• Language: English