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Title: Helical antiferromagnetic ordering in EuNi 1.95As 2 single crystals

Abstract

The Eu + 2 spins-7/2 in EuNi 2 As 2 with the body-centered tetragonal ThCr 2 Si 2 structure order antiferromagnetically below the Néel temperature T N = 15 K into a helical antiferromagnetic (AFM) structure with the helix axis aligned along the tetragonal c axis and the Eu ordered moments aligned ferromagnetically within the ab plane as previously reported from neutron diffraction measurements [T. Jin et al., Phys. Rev. B 99, 014425 (2019)]. Here we study the crystallographic, magnetic, thermal, and electronic transport properties of Bi-flux-grown single crystals using single-crystal x-ray diffraction, anisotropic magnetic susceptibility χ, isothermal magnetization M, heat capacity Cp, and electrical resistivity ρ measurements versus applied magnetic field H and temperature T. Vacancies are found on the Ni sites corresponding to the composition EuNi 1.95 (1) As 2. A good fit of the ρ (T) data by the Bloch-Grüneisen theory for metals was obtained. The χab (T) data below T N are fitted well by molecular field theory (MFT), and the helix turn angle kd and the Eu-Eu Heisenberg exchange constants are extracted from the fit parameters. The kd value is in good agreement with the neutron-diffraction result. The magnetic contribution to the zero-field heat capacitymore » below T N is also fitted by MFT. The isothermal in-plane magnetization M ab exhibits two metamagnetic transitions versus H, whereas M c (T = 2 K ) is nearly linear up to H = 14 T, both behaviors being consistent with MFT. The M c (H, T) , ρ(H c, T) , and Cp (H c , T) data yielded a H c- T phase diagram separating the AFM and paramagnetic phases in good agreement with MFT. Anisotropic χ(T) literature data for the ThCr 2 Si 2 -type helical antiferromagnet EuRh 2 As 2 were also fitted well by MFT. A comparison is made between the crystallographic and magnetic properties of ThCr 2 Si 2-type Eu M 2 Pn 2 compounds with M = Fe , Co, Ni, Cu, or Rh, and Pn = P or As, where only ferromagnetic and c -axis helical AFM structures are found.« less

Authors:
 [1]; ORCiD logo [2];  [2]; ORCiD logo [3]
  1. Ames Lab., and Iowa State Univ., Ames, IA (United States)
  2. Stockholm Univ. (Sweden)
  3. Ames Lab., and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1570835
Report Number(s):
IS-J-10052
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:  
AC02-07CH11358
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 100; Journal Issue: 9; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Sangeetha, N. S., Smetana, V., Mudring, A. -V., and Johnston, D. C. Helical antiferromagnetic ordering in EuNi1.95As2 single crystals. United States: N. p., 2019. Web. doi:10.1103/PhysRevB.100.094438.
Sangeetha, N. S., Smetana, V., Mudring, A. -V., & Johnston, D. C. Helical antiferromagnetic ordering in EuNi1.95As2 single crystals. United States. doi:10.1103/PhysRevB.100.094438.
Sangeetha, N. S., Smetana, V., Mudring, A. -V., and Johnston, D. C. Mon . "Helical antiferromagnetic ordering in EuNi1.95As2 single crystals". United States. doi:10.1103/PhysRevB.100.094438.
@article{osti_1570835,
title = {Helical antiferromagnetic ordering in EuNi1.95As2 single crystals},
author = {Sangeetha, N. S. and Smetana, V. and Mudring, A. -V. and Johnston, D. C.},
abstractNote = {The Eu+ 2 spins-7/2 in EuNi2 As2 with the body-centered tetragonal ThCr2 Si2 structure order antiferromagnetically below the Néel temperature TN = 15 K into a helical antiferromagnetic (AFM) structure with the helix axis aligned along the tetragonal c axis and the Eu ordered moments aligned ferromagnetically within the ab plane as previously reported from neutron diffraction measurements [T. Jin et al., Phys. Rev. B 99, 014425 (2019)]. Here we study the crystallographic, magnetic, thermal, and electronic transport properties of Bi-flux-grown single crystals using single-crystal x-ray diffraction, anisotropic magnetic susceptibility χ, isothermal magnetization M, heat capacity Cp, and electrical resistivity ρ measurements versus applied magnetic field H and temperature T. Vacancies are found on the Ni sites corresponding to the composition EuNi1.95 (1) As 2. A good fit of the ρ (T) data by the Bloch-Grüneisen theory for metals was obtained. The χab (T) data below TN are fitted well by molecular field theory (MFT), and the helix turn angle kd and the Eu-Eu Heisenberg exchange constants are extracted from the fit parameters. The kd value is in good agreement with the neutron-diffraction result. The magnetic contribution to the zero-field heat capacity below TN is also fitted by MFT. The isothermal in-plane magnetization Mab exhibits two metamagnetic transitions versus H, whereas Mc (T = 2 K ) is nearly linear up to H = 14 T, both behaviors being consistent with MFT. The Mc (H, T) , ρ(Hc, T) , and Cp (H c , T) data yielded a Hc- T phase diagram separating the AFM and paramagnetic phases in good agreement with MFT. Anisotropic χ(T) literature data for the ThCr 2 Si2 -type helical antiferromagnet EuRh2 As2 were also fitted well by MFT. A comparison is made between the crystallographic and magnetic properties of ThCr2 Si2-type Eu M2 Pn2 compounds with M = Fe , Co, Ni, Cu, or Rh, and Pn = P or As, where only ferromagnetic and c -axis helical AFM structures are found.},
doi = {10.1103/PhysRevB.100.094438},
journal = {Physical Review B},
number = 9,
volume = 100,
place = {United States},
year = {2019},
month = {9}
}

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Works referenced in this record:

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