ΜSR study of spin freezing and persistent spin dynamics in NaCaNi2F7. (29th August 2018)

• Record Type: Journal Article
• Authors: Cai, Y; Wilson, M N; Hallas, A M; Liu, L; Frandsen, B A; Dunsiger, S R; Krizan, J W; Cava, R J; Rubel, O; Uemura, Y J; Luke, G M
• Is Part Of: Journal of physics. Volume 30:Number 38(2018)
• Publication Date: 2018-08-29
• Subjects: μSR -- pyrochlore -- NaCaNi2F7 -- frustrated magnetic -- spin dynamics; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aad91c
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: A new pyrochlore compound, NaCaNi2 F7, was recently synthesized and has a single magnetic site with spin-1 Ni 2+ . We present zero field and longitudinal field muon spin rotation ( μ SR) measurements on this pyrochlore. Density functional theory calculations show that the most likely muon site is located between two fluorine ions, but off-centre. A characteristic F- μ -F muon spin polarization function is observed at high temperatures where Ni spin fluctuations are sufficiently rapid. The Ni 2+ spins undergo spin freezing into a disordered ground state below 4 K, with a characteristic internal field strength of 140 G. Persistent Ni spin dynamics are present to our lowest temperatures (75 mK), a feature characteristic of many geometrically frustrated magnetic systems.