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Title: Doping evolution of the second magnetization peak and magnetic relaxation in ( B a 1 - x K x ) F e 2 A s 2 single crystals

Abstract

Here, we present a thorough study of doping dependent magnetic hysteresis and relaxation characteristics in single crystals of (Ba 1-xK x) Fe 2As 2 (0.18 ≤ x ≤ 1). The critical current density J c reaches maximum in the underdoped sample x = 0.26 and then decreases in the optimally doped and overdoped samples. Meanwhile, the magnetic relaxation rate S rapidly increases and the flux creep activation barrier U 0 sharply decreases in the overdoped sample x = 0.70. These results suggest that vortex pinning is very strong in the underdoped regime, but it is greatly reduced in the optimally doped and overdoped regime. Transmission electron microscope (TEM) measurements reveal the existence of dislocations and inclusions in all three studied samples x = 0.38, 0.46, and 0.65. An investigation of the paramagnetic Meissner effect (PME) suggests that spatial variations in T c become small in the samples x = 0.43 and 0.46, slightly above the optimal doping levels. Our results support that two types of pinning sources dominate the (Ba 1-xK x) Fe 2As 2 crystals: (i) strong δl pinning, which results from the fluctuations in the mean free path l and δT c pinning from the spatial variations inmore » T c in the underdoped regime, and (ii) weak δT c pinning in the optimally doped and overdoped regime.« less

Authors:
 [1];  [1];  [1];  [1];  [2];  [2];  [3]
  1. Ames Lab., Ames, IA (United States). Division of Materials Sciences and Engineering
  2. Ames Lab. and Iowa State Univ., Ames, IA (United States). Division of Materials Sciences and Engineering and Dept. of Physics and Astronomy
  3. Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Materials Science and Engineering
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE
OSTI Identifier:
1422753
Alternate Identifier(s):
OSTI ID: 1421577
Report Number(s):
IS-J-9358
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US1801652
Grant/Contract Number:  
AC02-07CH11358
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 5; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Liu, Yong, Zhou, Lin, Sun, Kewei, Straszheim, Warren E., Tanatar, Makariy A., Prozorov, Ruslan, and Lograsso, Thomas A. Doping evolution of the second magnetization peak and magnetic relaxation in (Ba1-xKx)Fe2As2 single crystals. United States: N. p., 2018. Web. doi:10.1103/PhysRevB.97.054511.
Liu, Yong, Zhou, Lin, Sun, Kewei, Straszheim, Warren E., Tanatar, Makariy A., Prozorov, Ruslan, & Lograsso, Thomas A. Doping evolution of the second magnetization peak and magnetic relaxation in (Ba1-xKx)Fe2As2 single crystals. United States. doi:10.1103/PhysRevB.97.054511.
Liu, Yong, Zhou, Lin, Sun, Kewei, Straszheim, Warren E., Tanatar, Makariy A., Prozorov, Ruslan, and Lograsso, Thomas A. Fri . "Doping evolution of the second magnetization peak and magnetic relaxation in (Ba1-xKx)Fe2As2 single crystals". United States. doi:10.1103/PhysRevB.97.054511. https://www.osti.gov/servlets/purl/1422753.
@article{osti_1422753,
title = {Doping evolution of the second magnetization peak and magnetic relaxation in (Ba1-xKx)Fe2As2 single crystals},
author = {Liu, Yong and Zhou, Lin and Sun, Kewei and Straszheim, Warren E. and Tanatar, Makariy A. and Prozorov, Ruslan and Lograsso, Thomas A.},
abstractNote = {Here, we present a thorough study of doping dependent magnetic hysteresis and relaxation characteristics in single crystals of (Ba1-xKx) Fe2As2 (0.18 ≤ x ≤ 1). The critical current density Jc reaches maximum in the underdoped sample x = 0.26 and then decreases in the optimally doped and overdoped samples. Meanwhile, the magnetic relaxation rate S rapidly increases and the flux creep activation barrier U0 sharply decreases in the overdoped sample x = 0.70. These results suggest that vortex pinning is very strong in the underdoped regime, but it is greatly reduced in the optimally doped and overdoped regime. Transmission electron microscope (TEM) measurements reveal the existence of dislocations and inclusions in all three studied samples x = 0.38, 0.46, and 0.65. An investigation of the paramagnetic Meissner effect (PME) suggests that spatial variations in Tc become small in the samples x = 0.43 and 0.46, slightly above the optimal doping levels. Our results support that two types of pinning sources dominate the (Ba1-xKx) Fe2As2 crystals: (i) strong δl pinning, which results from the fluctuations in the mean free path l and δTc pinning from the spatial variations in Tc in the underdoped regime, and (ii) weak δTc pinning in the optimally doped and overdoped regime.},
doi = {10.1103/PhysRevB.97.054511},
journal = {Physical Review B},
number = 5,
volume = 97,
place = {United States},
year = {Fri Feb 16 00:00:00 EST 2018},
month = {Fri Feb 16 00:00:00 EST 2018}
}

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Works referenced in this record:

Flux vortices and transport currents in type II superconductors
journal, March 1972