An investigation using thermal phonons of the concentration dependence of V<sup>3+</sup> frequency crossing signals in Al<sub>2</sub>O<sub>3</sub>
L J Challis; D L Williams; L J Challis; Dept. of Phys., Univ. of Nottingham, Nottingham, UK; D L Williams; Dept. of Phys., Univ. of Nottingham, Nottingham, UK
Журнал:
Journal of Physics C: Solid State Physics
Дата:
1978-09-28
Аннотация:
Measurements have been made of the concentration dependence of the size of the frequency crossing signals due to V<sup>3+</sup> ions in Al<sub>2</sub>O<sub>3</sub>. These occur in the low-temperature thermal magnetoresistance at 3.1 T for fields along the c axis. The signal height varies approximately as (concentration)<sup>0.7</sup> and the width as (concentration)<sup>0.15</sup> and these variations are shown to be consistent with theoretical analysis when account is taken of the hyperfine splitting of the V<sup>3+</sup> levels. The data confirm that the Delta M=2 transition is much more strongly coupled to the lattice than the Delta M=1 transition and lead to values of (G<sub>44</sub><sup>2</sup>+G<sub>51</sub><sup>2</sup>)<sup>1</sup>2/=15+or-5 cm<sup>-1</sup> and (<sup>1</sup>/<sub>2</sub>G<sup>2</sup>+2G<sub>15</sub><sup>2</sup>)<sup>1</sup>2/=425+or-210 cm<sup>-1</sup>.
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