Title: Noncollinear magnetic structure and anisotropic magnetoelastic coupling in cobalt pyrovanadate $$\mathrm{Co_2V_2O_7}$$

Abstract

$$\mathrm{Co_2V_2O_7}$$ was recently reported to exhibit remarkable magnetic-field-induced magnetization plateaus and ferroelectricity, but its magnetic ground state remains ambiguous. Magnetometry measurements and time-of-flight neutron powder diffraction (NPD) have been employed to study the structural and magnetic properties of $$\mathrm{Co_2V_2O_7}$$, which includes two nonequivalent Co sites. Upon cooling below the Néel temperature $$T_N = 6.0(2)$$ K, we observe magnetic Bragg peaks at 2 K in NPD, which indicates the formation of long-range magnetic order of $$\mathrm{Co^{2+}}$$ moments. After symmetry analysis and magnetic structure refinement, we demonstrate that $$\mathrm{Co_2V_2O_7}$$ possesses a complicated noncollinear magnetic ground state with Co moments mainly located in the b-c plane and forming a noncollinear spin-chain-like structure along the c-axis. The ab initio calculations demonstrate that the noncollinear magnetic structure is more stable than various ferromagnetic states at low temperature. The noncollinear magnetic structure with a canted ↑↑↓↓ spin configuration is considered to be the origin of magnetoelectric coupling in$$\mathrm{Co_2V_2O_7}$$ because the inequivalent exchange striction induced by the spin-exchange interaction between the neighboring spins could be the driving force of ferroelectricity. Finally, it is also found that the deviation of lattice parameters a and b is opposite below $$T_N$$, while the lattice parameter c and $$β$$ stay almostmore » constant below $$T_N$$, evidencing the anisotropic magnetoelastic coupling in $$\mathrm{Co_2V_2O_7}$$.« less

Authors:

Ji, W. H. ^[1]; Yin, L. ^[2]; Zhu, W. M. ^[3]; Kumar, C. M. N.  ^[4];

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Li, C. ^[5]; Li, H. -F. ^[6]; Jin, W. T. ^[7]; Nandi, S. ^[1]; Sun, X. ^[1]; Su, Y. ^[7]; Brückel, Th. ^[1]; Lee, Y. ^[8]; Harmon, B. N. ^[8]; Ke, L. ^[8]; Ouyang, Z. W.  ^[2];

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Xiao, Y. ^[3]

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+ Show Author Affiliations

1. Jülich Aachen Research Alliance - Fundamentals of Future Information Technology (JARA-FIT), Jülich (Germany). Jülich Centre for Neutron Science (JCNS), and Peter Grünberg Institut (PGI)
2. Huazhong Univ. of Science and Technology, Wuhan (China). Wuhan National High Magnetic Field Center
3. Peking Univ., Shenzhen (China). Shenzhen Graduate School, School of Advanced Materials
4. Inst. für Festkörperphysik, Wien (Austria)
5. Jülich Centre for Neutron Science (JCNS), Outstation at Spallation Neutron Source (SNS), Oak Ridge, TN (United States)
6. Univ. of Macau, Taipa (China). Joint Key Lab. of the Ministry of Education, and Inst. of Applied Physics and Materials Engineering
7. Jülich Centre for Neutron Science (JCNS), Garching (Germany)
8. Ames Lab., Ames, IA (United States)

Publication Date:

Mon Oct 14 00:00:00 EDT 2019

Research Org.:

Ames Laboratory (AMES), Ames, IA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1572383

Report Number(s):

IS-J 10063
Journal ID: ISSN 2469-9950; PRBMDO; TRN: US2100042

Grant/Contract Number:  

11874023; 2016-6041; SRG2016-00091-FST; 063/2016/A2; 064/2016/A2; 028/2017/A1; 0051/2019/AFJ; AC02-07CH11358; AC02-05CH11231

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 100; Journal Issue: 13; 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