Low-energy Raman scattering fromCo2+electronic transitions in CdS:Co

Spin-manipulated phonon dynamics during magnetic phase transitions in triangular lattice antiferromagnet CuCr1−xMgxO2 semiconductor films

“…31 On the other hand, the Cr 3+ levels for CuCr 1Àx Mg x O 2 in an octahedral environment contain two low lying spin-allowed (but dipole forbidden) excitations derived from the 4 T 2g and 4 T 1g states of the excited t 2 2g e 1 g conguration. 33 According to the Tanabe-Sugano diagram, the increasing octahedral eld with decreasing temperature drives the ground state shis from the 4 T 2g to 4 T 1g , and nally turns D SIA negative at a certain temperature T N2 around 23 K. 34,35 On the other hand, the typical 120 spin structure of TLA is determined by the sign of D SIA . 33 According to the Tanabe-Sugano diagram, the increasing octahedral eld with decreasing temperature drives the ground state shis from the 4 T 2g to 4 T 1g , and nally turns D SIA negative at a certain temperature T N2 around 23 K. 34,35 On the other hand, the typical 120 spin structure of TLA is determined by the sign of D SIA .…”

“…32 The octahedral crystal-eld distortion splits the ground states by an energy associated with D SIA , although the single-ion anisotropy splitting is normally quite small. 33 According to the Tanabe-Sugano diagram, the increasing octahedral eld with decreasing temperature drives the ground state shis from the 4 T 2g to 4 T 1g , and nally turns D SIA negative at a certain temperature T N2 around 23 K. 34,35 On the other hand, the typical 120 spin structure of TLA is determined by the sign of D SIA . For a triangular antiferromagnet with positive D SIA , the spin spiral plane for the 120 structure is parallel to the triangular lattice plane (TLP), while the 120 structure shows an out-of-plane characteristic for those with negative D SIA .…”