Mn<sup>2+</sup> EPR study of the phase transition in langbeinite Cd<sub>2</sub>(NH<sub>4</sub>)<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>
S K Misra; S Z Korczak; S K Misra; Dept. of Phys., Concordia Univ., Montreal, Que., Canada; S Z Korczak; Dept. of Phys., Concordia Univ., Montreal, Que., Canada
Журнал:
Journal of Physics C: Solid State Physics
Дата:
1986-08-10
Аннотация:
The phase transition in the langbeinite Cd<sub>2</sub>(NH<sub>4</sub>)<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> has been studied via the EPR of Mn<sup>2+</sup>. The phase transition temperature has been determined to be T<sub>c</sub>=94.5+or-0.5K. The spin-Hamiltonian parameters have been computed using a rigorous least-squares fitting procedure, numerically diagonalising the spin Hamiltonian and simultaneously fitting a large number of EPR line positions obtained for several orientations of the external magnetic field on a digital computer. It is suggested that the phase transition below T<sub>c</sub> is due to the freezing of (SO<sub>4</sub>)<sup>2-</sup> rotations.
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