Relaxation of muon spins in molecular nanomagnets

Article, Preprint OPEN
T. Lancaster, S. J. Blundell, F. L. Pratt, I. Franke, A. J. Steele, P. J. Baker, Z. Salman, C. Baines, I. Watanabe,S. Carretta, G. A. Timco and R. E. P. Winpenny (2010)
  • Publisher: AMER PHYSICAL SOC
  • Journal: (issn: 1098-0121)
  • Related identifiers: doi: 10.1103/PhysRevB.81.140409
  • Subject: /dk/atira/pure/subjectarea/asjc/3100/3104 | /dk/atira/pure/subjectarea/asjc/2500/2504 | Condensed Matter - Strongly Correlated Electrons | Condensed Matter Physics | Electronic, Optical and Magnetic Materials
    arxiv: Condensed Matter::Strongly Correlated Electrons

We address the cause of the unusual muon spin-relaxation (μ+ SR) results on molecular nanomagnets (MNMs). Through measurements on protonated and deuterated samples of the MNMs Cr7 Mn (S=1) and Cr8 (S=0), we show that the muon spin for S≠0 MNMs is relaxed via dynamic fluctuations of the electronic spins. A freezing out of dynamic processes occurs on cooling and at low temperatures the muon spins are relaxed by the electronic spins which themselves are dephased by incoherent nuclear-field fluctuations. We observe a transition to a state of static magnetic order of the MNM electronic spins in Cr7Mn below 2 K. © 2010 The American Physical Society.