Pressure effects on structural and electronic properties of superconductors
HIGH-PRESSURE CRYSTALLOGRAPHY 140 (2004) 429-446
Spin singlet formation in MgTi$_2$O$_4$: evidence of a helical dimerization pattern
(2003)
Spin singlet formation in MgTi$_2$O$_4$: evidence of a helical dimerization pattern
ArXiv cond-mat/0308101 (2003)
Abstract:
The transition metal spinel MgTi$_2$O$_4$ undergoes a metal-insulator transition on cooling below $T_{M-I} = 260$ K. A sharp reduction of the magnetic susceptibility below $T_{M-I}$ suggests the onset of a magnetic singlet state. Using high-resolution synchrotron and neutron powder diffraction, we have solved the low-temperature crystal structure of MgTi$_2$O$_4$, which is found to contain dimers with short Ti-Ti distances (the locations of the spin singlets) alternating with long bonds to form helices. Band structure calculations based on hybrid exchange density functional theory show that, at low temperatures, MgTi$_2$O$_4$ is an orbitally ordered band insulator.High Performances Corrugated Feed Horns for Space Applications at Millimetre Wavelengths
(2003)