Reaching the equilibrium spin structure of Ca<sub>3</sub>Co<sub>2</sub>O<sub>6</sub> Ising triangular frustrated magnet at low temperatures

POSTER

Abstract

Understanding the observed metastable magnetization steps vs magnetic field with very slow dynamics in Ca3Co2O6 Ising triangular frustrated magnet poses a long-standing challenge. We make a step forward in solving this puzzle by conducting a detailed study of the ground state of this spin system in temperatures below 4 K. Our work shows that the ground state can be reached at low temperatures by cooling down Ca3Co2O6 single crystal in fields ranging from 0.125T to 3.6T oriented parallel to its easy-magnetization axis. Through this procedure we achieve a predicted ground state at 2 K and explore stability of this state by time-relaxation measurements. We do not however succeed in approaching the ground state with quantum annealing in transverse magnetic fields of up to 7 T, likely due to the large Ising anisotropy of the Co spins. We compare our equilibrium experimental data for Ca3Co2O6 spin system to the quantum Monte Carlo simulations of a modified version of the Axial Next-Nearest-Neighbor Ising (ANNNI) model. This modified ANNNI model is derived for Ca3Co2O6 by interleaving three chains to form one effective spin chain with frustrated nearest, next-nearest and next-next-nearest neighbor interactions.

*We are grateful to Cristian Batista for valuable discussions. Scientific work at LANL was funded by the LDRD program at LANL. The facilities of the NHMFL are funded by the U.S. NSF through Cooperative Grant No.DMR-1157490, the U.S. DOE and the Stateof Florida. L.C. and I.N. research supported by the US DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering. Y.K. acknowledges the support by the NSFC (No. 11950410507, No. 12074246, and No. U2032213) and MOST (No. 2016YFA0300500 and No. 2016YFA0300501) research programs.

Publication: Planned submission: "Reaching the equilibrium state of frustrated triangular Ising magnet Ca3Co2O6"

Presenters

  • Ivan Nekrashevich

    • Los Alamos National Laboratory
    • Los Alamos National Laboratory, Department of Integrated Bio & Nano Systems, University of Houston
    • Superconducting Quantum Materials and Systems, Fermi National Accelerator Laboratory

Authors

  • Ivan Nekrashevich

    • Los Alamos National Laboratory
    • Los Alamos National Laboratory, Department of Integrated Bio & Nano Systems, University of Houston
    • Superconducting Quantum Materials and Systems, Fermi National Accelerator Laboratory

  • Xiaxin Ding

    • City College of New York
    • The City College of New York

  • Fedor F Balakirev

    • Los Alamos Natl Lab

  • Hee Taek Yi

    • Rutgers, The State University of New Jersey
    • Rutgers University

  • Sang-Wook Cheong

    • Rutgers University, New Brunswick
    • Rutgers University

  • Leonardo Civale

    • Los Alamos Natl Lab

  • Yoshitomo Kamiya

    • Shanghai Jiao Tong Univ
    • Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education),Shenyang National Laboratory for Materials Science, School of Physics and Astronomy,Shangha

  • Vivien Zapf

    • Los Alamos Natl Lab
    • Los Alamos National Laboratory