Abstract
Three paramagnetic centers associated with manganese substituting for have been observed at 300 K by EPR in reduced crystals of SrTi. The first is a ion having cubic symmetry, with isotropic and values given by and . The second center is characterized by an axially symmetric EPR spectrum with effective values of and at band. The spectrum is attributed to transitions between the levels of a ion located in a strong tetragonal crystalline field. The tetragonal field presumably arises from a nearest-neighbor oxygen vacancy, hence we designate it as , in analogy with the previously investigated center. An exact computer diagonalization of the matrix, together with data on a second fine-structure transition, yielded a zero-field splitting parameter , and values of and . The hyperfine-structure splitting parameters were determined to be and . The normally forbidden transitions were also observed for this center, and their separations are consistent with an formalism. The third paramagnetic center also gives rise to a highly-anisotropic spectrum with effective values of and , and a hyperfine constant . The center is assigned to a ion associated with a nearest-neighbor oxygen vacancy, hence we designate it as . The one fine-structure transition observed is assigned to occur between the levels of . By careful measurements at - and -band frequencies, the cubic zero-field splitting between these levels was determined to be .
- Received 21 March 1977
DOI:https://doi.org/10.1103/PhysRevB.16.4761
©1977 American Physical Society