Glassy correlated state induced by disorder in the frustrated antiferromagnet Tb2Zr2O7

• Published in: Journal of magnetism and magnetic materials 2023-01, Vol.565, p.170215, Article 170215
• Main Authors: Ramon, J.G.A., Silva, P.L.O., Gardner, J.S., Freitas, R.S.
• Format: Article
• Language: English
• Subjects: Fluorite; Magnetic frustration; MATERIALS SCIENCE; Spin glass; Zirconate
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2022.170215

•No long-range magnetic order is found on Tb2Zr2O7 but antiferromagnetic correlations between spins that remain dynamic at low temperatures.•The zirconate Tb2Zr2O7 enters into a disordered glassy-like state below ∼ 2.2 K which is defect-induced by the site mixing and frustration of its magnetic units.•Many similarities between Tb2Zr2O7 and others Tb-based pyrochlore systems exhibiting liquidness and highly correlated phases are found. We study the low-temperature thermomagnetic properties of the polycrystalline material Tb2Zr2O7 through ac susceptibility and specific heat measurements. This zirconate displays a defect-fluorite structure in which the magnetic Tb3+ and nonmagnetic Zr4+ cations sit randomly on the same metal sublattice. No long-range magnetic order is found down to 100 mK, although dominant antiferromagnetic interactions are observed and the spins remain dynamic down to the lowest temperatures investigated. We observed a frequency-dependent peak around 2.5 K which is well described by many models of a canonical spin-glass transition. In-field specific heat measurements and the recovered entropy of the system Rln(4) suggest a two doublets ground state separated by 7 K. Comparisons to the pyrochlores Tb2Ti2O7 and Tb2Hf2O7 reinforce the collective spin-glass-type behavior and the opening for discussions of an exotic Coulomb phase in this material.