Title: Spin-Frustrated Pyrochlore Chains in the Volcanic Mineral Kamchatkite (KCu3OCl(SO4)2),
Abstract: Search of new frustrated magnetic systems is of a significant importance for
physics studying the condensed matter. The platform for geometric frustration
of magnetic systems can be provided by copper oxocentric tetrahedra (OCu4)
forming the base of crystalline structures of copper minerals from Tolbachik
volcanos in Kamchatka. The present work was devoted to a new frustrated
antiferromagnetic - kamchatkite (KCu3OCl(SO4)2). The calculation of the sign
and strength of magnetic couplings in KCu3OCl(SO4)2 has been performed on the
basis of structural data by the phenomenological crystal chemistry method with
taking into account corrections on the Jahn-Teller orbital degeneracy of Cu2.
It has been established that kamchatkite (KCu3OCl(SO4)2) contains AFM
spin-frustrated chains of the pyrochlore type composed of cone-sharing Cu4
tetrahedra. Strong AFM intrachain and interchain couplings compete with each
other. Frustration of magnetic couplings in tetrahedral chains is combined with
the presence of electric polarization.