title: Field-induced transition of the magnetic ground state from A-type antiferromagnetic to ferromagnetic order in CsCo2Se2.
abstract: We report on the magnetic properties of CsCo2Se2 with ThCr2Si2 structure, which we have characterized through a series of magnetization and neutron diffraction measurements. We find that CsCo2Se2 undergoes a phase transition to an antiferromagnetically ordered state with a Néel temperature of [Formula: see text] K. The nearest neighbour interactions are ferromagnetic as observed by the positive Curie-Weiss temperature of [Formula: see text] K. We find that the magnetic structure of CsCo2Se2 consists of ferromagnetic sheets, which are stacked antiferromagnetically along the tetragonal c-axis, generally referred to as A-type antiferromagnetic order. The observed magnitude of the ordered magnetic moment at T  =  1.5 K is found to be only 0.20(1)[Formula: see text] / Co. Already in comparably small magnetic fields of [Formula: see text] T, we observe a metamagnetic transition that can be attributed to spin-rearrangements of CsCo2Se2, with the moments fully ferromagnetically saturated in a magnetic field of [Formula: see text] T. We discuss the entire experimentally deduced magnetic phase diagram for CsCo2Se2 with respect to its unconventionally weak magnetic coupling. Our study characterizes CsCo2Se2, which is chemically and electronically posed closely to the A x Fe2-y Se2 superconductors, as a host of versatile magnetic interactions.
authors.affiliation: Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland. Department of Chemistry, University of Munich (LMU), D-81377 Munich, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: von Rohr
authors.forename: Anna
authors.initials: A
authors.lastname: Krzton-Maziopa
authors.forename: Vladimir
authors.initials: V
authors.lastname: Pomjakushin
authors.forename: Henrik
authors.initials: H
authors.lastname: Grundmann
authors.forename: Zurab
authors.initials: Z
authors.lastname: Guguchia
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schnick
authors.forename: Andreas
authors.initials: A
authors.lastname: Schilling