| Incommensurate phase of quartz : I. Elastic neutron scattering (1984) | |||||||||||||||
Abstract | |||||||||||||||
| We report on elastic neutron scattering results showing that the intermediate phase of quartz existing in a 1.3 K range between the α and β phases is in fact incommensurate. Six satellites are observed around most Bragg peaks along the three [100] directions of reciprocal space. The modulation corresponds to the superposition of sinusoidal plane waves as no higher order harmonics are observed. With decreasing temperature the modulation vector decreases from 0.033 to 0.029 reciprocal units. Premonitory diffuse scattering is observed in the β phase a few degrees above Ti = 847.2 K, the incommensurate transition temperature. The results are discussed in relation with the current theories of incommensurate phases and are in many respect analogous to the situation of NaNO2. | |||||||||||||||
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