Hysteresis in the spin transition regime of [Fe(NH2trz)3](NO3)2 as probed by ZF-μSR

The thermal spin transition which occurs in the polymeric chain compound [Fe(NH2trz)3](NO3)2 above room temperature has been investigated by zero-field muon spin relaxation (μSR) (∼8–402 K). The depolarization curves are best described by a Lorentzian and a Gaussian line that represent fast and slow components respectively. The spin transition is associated with a hysteresis loop of width ΔT=34K (T1/2↑=346K and T1/2↓=312K) that has been delineated by the temperature variation of the initial asymmetry parameter. Comparison of zero-field and transverse field (20 Oe) μSR measurements shows that diamagnetic muon species occur over the entire temperature range, a large fraction of muons being however paramagnetic.