Magnetic Susceptibility Measurements of Rutile and the Magnéli Phases of the Ti-O System

Abstract

Magnetic-susceptibility measurements of the Magneli phases of the Ti-0 system show a change from weak covalent bond formation, through antiferromagnetic to paramagnetic-like behavior with increasing oxygen concentration. The reciprocal molar susceptibility plotted versus temperature indicates collective electron effects in all phases except TiOi.50 and TiOi.67. These exhibit noncooperative and cooperative semiconductor-to-metal transitions, respectively.

Toward tailored functionality of titania nanotube arrays: Interpretation of the magnetic-structural correlations

“…Expansion of the unit cell volume and enhanced localized magnetism in nominally pure anatase NTs are consistent with the presence of oxygen vacancies ( € V O , in Kröger-Vink notation 29 ) in these nanostructures that trap electrons at low temperature. While stoichiometric titania contains only Ti 41 ions and is considered to have a temperature-independent magnetic susceptibility, 30,31 annealing in oxygen-deficient or reducing environments produces charged structural defects, such as oxygen vacancies. 32 TABLE I. Fitting parameters for the measured total magnetic susceptibility, v tot ðTÞ ¼ C=ðT À T 0 Þ þ v pp , Eq.…”

Cathodoluminescence and room temperature ferromagnetism of Mn-doped ZnO nanorod arrays grown by chemical vapor deposition

“…The inset of Fig. 21,22 As a result, the antiferromagnetic interaction suppresses the ferromagnetic coupling, which results in the disappearance of ferromagnetism in Mn-doped ZnO nanorods. The temperature dependence of magnetization is obtained by performing field cooled ͑FC͒ and zero field cooled ͑ZFC͒ magnetization measurements at the temperature range of 2 -300 K. It is clear from the figure that the FC and ZFC curves remain separated throughout the entire temperature range ͑2 -300 K͒, while they coincide around 305 K by extrapolating these two curves.…”

Thermodynamics of oxygen defective Magnéli phases in rutile: A first-principles study

“…At temperatures below 150 K, Ti 4 O 7 is antiferromagnetic. 30,31 The subject of the current work is the thermodynamic stability of defect phases, which has been measured in a series of experimental studies. In their seminal paper on higher titanium oxides, Bursill and Hyde 3 performed an analysis of the thermodynamics of the Magnéli phases with 4 ഛ n ഛ 10.…”