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Spin freezing and dynamics in Ca3Co2-xMnxO6 (x≈0.95) investigated with implanted muons: Disorder in the anisotropic next-nearest-neighbor Ising model

Physical review. B, Condensed matter (Impact Factor: 3.66). 01/2009; 80. DOI: 10.1103/PhysRevB.80.020409

ABSTRACT We present a muon-spin relaxation investigation of the Ising chain magnet Ca3Co2-xMnxO6 (x≈0.95) . We find dynamic spin fluctuations persisting down to the lowest measured temperature of 1.6 K. The previously observed transition at around 18K is interpreted as a subtle change in dynamics for a minority of the spins coupling to the muon that we interpret as spins locking into clusters. The dynamics of this spin fraction freeze below a temperature TSF≈8K , while a majority of spins continue to fluctuate. An explanation of the low-temperature behavior is suggested in terms of the predictions of the anisotropic next-nearest-neighbor Ising model.

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