Electron Spin Resonance of Cu²⁺ and Ni³⁺ in Mg₂TiO₄

Abstract

Electron spin resonances of Cu²⁺ and Ni³⁺ in Mg₂TiO₄ grown by the travelling solvent float zone (TSFZ) method were measured at 4.2 K, 77 K and 297 K. Both impurity ions substitute the octahedral Mg²⁺ site and are subject to a tetragonal crystal field caused by the Jahn-Teller effect. The spin Hamiltonian parameters of Cu²⁺ whose ground state has an unpaired hole in d_x²−y² are g_⁄⁄=2.333, g_⊥=2.080, A_⁄⁄=108×10⁻⁴ cm⁻¹ and A_⊥=0 cm⁻¹ and those of Ni³⁺ whose ground state has an unpaired electron in d_z² are g_⁄⁄=2.048 and g_⊥=2.239.