Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Magnetic Order and Fluctuations in the Presence of Quenched Disorder in the Kagome Staircase System (Co1-xMgx)3V2O8

Published

Author(s)

K. Fritsch, Zahra Yamani, S. Chang, Yiming Qiu, John R. Copley, M. Ramazanoglu, H. A. Dabkowska, B. D. Gaulin

Abstract

Co3V2O8 is an orthorhombic magnet in which S=3/2} magnetic moments reside on two crystallographically inequivalent Co2+ sites, which decorate a stacked, buckled version of the two dimensional kagome lattice, the stacked kagome staircase. The magnetic interactions between the Co2+ moments in this structure lead to a complex magnetic phase diagram at low temperature, wherein it exhibits a series of five transitions below 11 K that ultimately culminate in a simple ferromagnetic ground state below Tapprox.}6.2 K. Here we report magnetization measurements on single and polycrystalline samples of (Co1-xMgx)3V2O8 for xless than}0.23. as well as elastic and inelastic neutron scattering measurements on single crystals of magnetically dilute (Co1-xMgx)3V2O8 for x=0.029 and x=0.194, in which non-magnetic Mg2+ ions substitute for magnetic Co2+. We find that a dilution of 2.9% leads to a suppression of the ferromagnetic transition temperature by approx.} 15% while a dilution level of 19.4% is sufficient to destroy ferromagnetic long-range order in this material down to a temperature of at least 1.5 K. The magnetic excitation spectrum is characterized by two spin-wave branches in the ordered phase for (Co1-xMgx)3V2O8 (x=0.029), similar to that of the pure x=0 material, and by broad diffuse scattering at temperatures below 10 K in (Co1-xMgx)3V2O8 (x=0.194). Such a strong dependence of the transition temperatures to long range order in the presence of quenched non-magnetic impurities is consistent with two-dimensional physics driving the transitions. We further provide a simple percolation model that semi-quantitatively explains the inability of this system to establish long-range magnetic order at the unusually-low dilution levels which we observe in our experiments.
Citation
Physical Review B
Volume
86
Issue
17

Keywords

kagome lattice, percolation model, magnetic order

Citation

Fritsch, K. , Yamani, Z. , Chang, S. , Qiu, Y. , Copley, J. , Ramazanoglu, M. , Dabkowska, H. and Gaulin, B. (2012), Magnetic Order and Fluctuations in the Presence of Quenched Disorder in the Kagome Staircase System (Co<sub>1-x</sub>Mg<sub>x</sub>)<sub>3</sub>V<sub>2</sub>O<sub>8</sub>, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=911718 (Accessed March 1, 2024)
Created November 20, 2012, Updated October 12, 2021