| dc.identifier.uri | http://hdl.handle.net/11401/76725 | |
| dc.description.sponsorship | This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree. | en_US |
| dc.format | Monograph | |
| dc.format.medium | Electronic Resource | en_US |
| dc.language.iso | en_US | |
| dc.publisher | The Graduate School, Stony Brook University: Stony Brook, NY. | |
| dc.type | Dissertation | |
| dcterms.abstract | Iron-based superconductor KxFe2-ySe2 has generated considerable attention having higher critical temperature (~31 K)* than previously reported FeSe series (~8 K) and showing a unique phase separation with Fe vacancy order. We investigate the effect of the chemical substitution to the ground state and report various ground states such as spin glass phase and superconductor-insulator transition (SIT) under high-magnetic field by substitution of Na, Te, and Ni on KxFe2-ySe2 single crystal. The normal-state in-plane resistivity below Tc and the upper critical field for KxFe2-ySe1.85Te0.15 and K0.50Na0.24Fe2-ySe2 are measured by suppressing superconductivity in pulsed magnetic fields. The normal-state resistivity is found to increase logarithmically as T/Tc goes to 0 with decreasing temperature similar to granular superconductors and Cu-based high-Tc superconductors. Our results suggest that SIT may be induced in high magnetic fields, which is related to the intrinsic real space phase separated states. We also present a ground state change of KxFe2-d-yNiySe2 (0.06<y<1.44) single crystal alloys. Small amount of Ni (~ 4%) substitution suppresses superconductivity below 1.8 K and for higher Ni content insulating spin glass magnetic ground state is induced. *Guo J G, Jin S F, Wang G, Wang S C, Zhu K X, Zhou T T, He M and Chen X L, Phys. Rev. B 82 180520 (R) (2010) | |
| dcterms.available | 2017-09-20T16:51:04Z | |
| dcterms.contributor | Stephens, Peter | en_US |
| dcterms.contributor | Petrovic, Cedomir | en_US |
| dcterms.contributor | Verbaarschot, Jacobus | en_US |
| dcterms.contributor | Khalid, Syed. | en_US |
| dcterms.creator | Ryu, Hyejin | |
| dcterms.dateAccepted | 2017-09-20T16:51:04Z | |
| dcterms.dateSubmitted | 2017-09-20T16:51:04Z | |
| dcterms.description | Department of Physics. | en_US |
| dcterms.extent | 121 pg. | en_US |
| dcterms.format | Application/PDF | en_US |
| dcterms.format | Monograph | |
| dcterms.identifier | http://hdl.handle.net/11401/76725 | |
| dcterms.issued | 2014-12-01 | |
| dcterms.language | en_US | |
| dcterms.provenance | Made available in DSpace on 2017-09-20T16:51:04Z (GMT). No. of bitstreams: 1
Ryu_grad.sunysb_0771E_12080.pdf: 9293238 bytes, checksum: 5ff38d6b6b49a0c1e8e6dc7f5efaee37 (MD5)
Previous issue date: 1 | en |
| dcterms.publisher | The Graduate School, Stony Brook University: Stony Brook, NY. | |
| dcterms.subject | Superconductivity | |
| dcterms.subject | Condensed matter physics | |
| dcterms.title | Phase separation and neighboring ground states of superconductivity in KxFe2− ySe2 | |
| dcterms.type | Dissertation | |
