| Summary: | Raman spectroscopy has been used to study the phonon-magnon coupling in the antiferromagnetic phase of ferrous chloride dihydrate. The interaction has been studied as a function of temperature, from 2 K to TN=23 K, and applied field, from 0 to 28 kG. The phonon is assigned as a Bg symmetry libration mode, in accord with the predictions of Torrance and Slonczewski; it is found to be "soft," decreasing in energy as T→0. The phonon-magnon coupling constant is nearly field independent but decreases to zero at TN. It is found that no zero-field splitting of the magnon occurs, within 0.2-cm-1 instrumental resolution, in contrast to the 0.8-cm-1 splitting inferred from the infrared spectrum. The magnon g value is determined to be 1.7 ± 0.1, in contrast to Torrance's value of 2.23 ± 0.02. © 1975 The American Physical Society.
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