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Title: Two-Dimensional J eff = 1 / 2 Antiferromagnetic Insulator Unraveled from Interlayer Exchange Coupling in Artificial Perovskite Iridate Superlattices

We report an experimental investigation of the two-dimensional J eff=1/2 antiferromagnetic Mott insulator by varying the interlayer exchange coupling in [(SrIrO 3) 1, (SrTiO 3) m] (m=1, 2 and 3) superlattices. Although all samples exhibited an insulating ground state with long-range magnetic order, temperature-dependent resistivity measurements showed a stronger insulating behavior in the m = 2 and m = 3 samples than the m = 1 sample which displayed a clear kink at the magnetic transition. This difference indicates that the blocking effect of the excessive SrTiO 3 layer enhances the effective electron-electron correlation and strengthens the Mott phase. The significant reduction of the Néel temperature from 150 K for m = 1 to 40 K for m = 2 demonstrates that the long-range order stability in the former is boosted by a substantial interlayer exchange coupling. Resonant x-ray magnetic scattering revealed that the interlayer exchange coupling has a switchable sign, depending on the SrTiO 3 layer number m, for maintaining canting-induced weak ferromagnetism. In conclusion, the nearly unaltered transition temperature between the m = 2 and the m = 3 demonstrated that we have realized a two-dimensional antiferromagnet at finite temperatures with diminishing interlayer exchange coupling.
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [4] ;  [5] ;  [5] ;  [5] ;  [6] ;  [2] ;  [1]
  1. Univ. of Tennessee, Knoxville, TN (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Charles Univ., Prague (Czech Republic)
  4. Charles Univ., Prague (Czech Republic); Academy of Sciences of the Czech Republic, Praha (Czech Republic)
  5. Argonne National Lab. (ANL), Argonne, IL (United States)
  6. Argonne National Lab. (ANL), Argonne, IL (United States); Dublin City Univ., Dublin (Ireland)
Publication Date:
Report Number(s):
BNL-114300-2017-JA; BNL-114704-2017-JA
Journal ID: ISSN 0031-9007; PRLTAO; 137004; TRN: US1702833
Grant/Contract Number:
AC02-06CH11357; 1047478; SC0012704
Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 119; Journal Issue: 2; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Early Career Award; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Scientific User Facilities Division; University of Tennessee; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1393207
Alternate Identifier(s):
OSTI ID: 1371508; OSTI ID: 1412641; OSTI ID: 1412745