Spin decoherence processes in the S=1/2 scalene triangular cluster (Cu-3(OH))

초록

We report the synthesis and magnetic properties of the molecular cluster Cu-3(mu(3) -OH)(mu-OH) (mu-O2Ar1F-Ph)(2)(py)(3)(OTf)(2), abbreviated as (Cu-3(OH)). Using magnetization, electron paramagnetic resonance and spin dimer analysis, we derive a microscopic magnetic model of (Cu-3(OH)) and measure the electron T-1 and T-2 relaxation times. The Cu2+ ions are arranged to form a distorted triangular structure with the three different exchange coupling constants J(1) = -43.5 K, J(2) = -53.0 K, and J(3) = -37.7 K. At T = 1.5 K T-1 is of the order of 10(-4) s and T-2 is evaluated to be 0.26 mu s. We find that the temperature dependence of 1/T-1 and 1/T-2 is governed by Orbach process and spin bath fluctuations, respectively. We discuss the role of spin-phonon mechanism in determining a spin decoherence time in a class of spin triangular clusters.

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