Interplay between structural and magnetic phase transitions in copper ferrite studied with high-resolution neutron diffraction

Tuning conductivity and magnetism of CuFe2O4via cation redistribution

“…CFO samples RQ-0, RQ-500, and RQ-900 are then roughly estimated to possess inversion parameters of 0.84, 0.79, and 0.74, respectively, which we believe to be reasonable according to previous reports and our calculations from PPMS and Mössbauer spectra. 10 These estimated inversion parameters are also very close to those from structure renement.…”

“…17,24 The geometric relaxation on CFO (l ¼ 1) unit cell leads to a tetragonal distortion, which matches well with the structure of the fully inverse T-CFO reported in literature. 10 The DOS calculated for the fully inverse CFO shows a band gap of 0.603 eV, as shown in Fig. 4(a), which shows semiconducting feature.…”

“…For CFO spinel, the decrease of inversion parameter l can be directly observed through the XRD analysis due to the symmetry transition from I4 1 /amd (tetragonal spinel phase) to Fd 3m (cubic spinel phase) induced by the gradual migration of Cu 2+ ions from O h site to T d site. 10 The Jahn-Teller distortion caused by Cu 2+ cations at O h site can be significantly suppressed as the inversion parameter l decreases. According to literatures, the process of cation redistribution would get enhanced and inversion parameter continuously decreases as the temperature gradually increases.…”

“…8,9 Copper ferrite (CuFe 2 O 4 ) which contains elements (Cu 2+ ions) with a high migration rate and low activation energy ($0.1 eV) is also an ideal candidate for ionic control of chemical states and magnetic properties. 10,11 Moreover, copper ferrite showing two phases (tetragonal spinel phase and cubic spinel phase) with large differences in physical properties differs from many spinel ferrites with only one cubic spinel phase. 12 The phase transition and physical properties of copper ferrite can also be easily modulated by cation redistribution between tetrahedral site (T d site or A site) and the octahedral site (O h site or B site) via thermal stimuli as previous studies indicated.…”

“…12 The phase transition and physical properties of copper ferrite can also be easily modulated by cation redistribution between tetrahedral site (T d site or A site) and the octahedral site (O h site or B site) via thermal stimuli as previous studies indicated. 10,13 The cation redistribution of copper ferrite leading to modulation of magnetic and magneto-optical properties have been well studied. 14,15 However, few attentions have been paid to the effect of cation redistribution on the electrical properties of copper ferrite, which still remains unclear.…”