Quasielastic and low-energy inelastic neutron scattering study of HoCrO₃by high resolution time-of-flight neutron spectroscopy

Abstract

n order to understand the origin of the huge quasielastic magnetic scattering
 observed previously with a back-scattering neutron spectrometer we
 have re-investigated the low energy excitations in HoCrO$_3$ by
 inelastic neutron scattering in a much wider energy range with
 time-of-flight neutron spectrometers. The inelastic signals are due to
 the excitations between the ground state doublet of the Ho ion. The quasielastic signal is due to the fluctuation of the disordered Ho moments. At low temperature the intensity of quasielastic scattering is small. It starts increasing as the temperature increases above 30 K. At the same temperature the elastic intensity due to Ho moment ordering decreases in a similar way. This observation strengthens the hypothesis that the quasielastic scattering is due the fluctuations of the disordered Ho moments. The time scale of fluctuations has been determine from the quasielastic scattering and was found to vary from about 22 ps at T = 70 K to about 2.5 ps at T = 160 K. The stretched exponential line shape indicates a distribution of decay rates at low temperatures.

Crystal growth engineering and origin of the weak ferromagnetism in antiferromagnetic matrix of orthochromates from t-e orbital hybridization

“…The previous study on polycrystalline HoCrO 3 sample shows μ eff – meas = 11.55 μ B and ( Su et al., 2011 ). Obtaining evidence of short-range exchange interactions and magnetic fluctuations of Ho 3+ spins reported previously by quasielastic and inelastic neutron scattering studies on HoCrO 3 powder samples ( Chatterji et al., 2017 ; Kumar et al., 2016 ) necessitates more in-house characterizations with the HoCrO 3 single crystal.…”