Origin of Ferromagnetism and its pressure and doping dependence in Tl${}_2$Mn${}_2$O${}_7$

Abstract

Using NMTO-{\it downfolding} technique, we explore and establish the origin of ferromagnetism in the pyrochlore system, Tl${}_2$Mn${}_2$O${}_7$. It is found to be driven by hybridization induced spin-polarization of the delocalized charge carriers derived from Tl-$s$ and O-$p$ states. The mean-field estimate of the ferromagnetic transition temperature, T${}_c$, estimated using computed exchange integrals are found to be in good agreement with the measurements. We find an enhancement of T${}_c$ for moderate doping with nonmagnetic Sb and a suppression of T${}_c$ upon application of pressure, both in agreement with experimental findings.

Accepted for publication in PRL

Cited by in corpus (1)

• Theoretical study of doped-Tl${}_2$Mn${}_2$O${}_7$ and Tl${}_2$Mn${}_2$O${}_7$ under pressure