title: First order metamagnetic transition in Ho2Ti2O7 observed by vibrating coil magnetometry at Milli-Kelvin temperatures.
abstract: We report vibrating coil magnetometry of the spin-ice system Ho(2)Ti(2)O(7) down to ~0.04 K for magnetic fields up to 5 T applied parallel to the [111] axis. History-dependent behavior emerges below T(0)(*) ~ 0.6 K near zero magnetic field, in common with other spin-ice compounds. In large magnetic fields, we observe a magnetization plateau followed by a hysteretic metamagnetic transition. The temperature dependence of the coercive fields as well as the susceptibility calculated from the magnetization identify the metamagnetic transition as a line of first order transitions terminating in a critical end point at T(m)(*) 0.37 ~/= K, B(m) ~/= 1.5 T. The metamagnetic transition in Ho(2)Ti(2)O(7) is strongly reminiscent of that observed in Dy(2)Ti(2)O(7), suggestive of a general feature of the spin ices.
authors.affiliation: Physik-Department E21, Technische Universität München, D-85748 Garching, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Krey
authors.forename: S
authors.initials: S
authors.lastname: Legl
authors.forename: S R
authors.initials: SR
authors.lastname: Dunsiger
authors.forename: M
authors.initials: M
authors.lastname: Meven
authors.forename: J S
authors.initials: JS
authors.lastname: Gardner
authors.forename: J M
authors.initials: JM
authors.lastname: Roper
authors.forename: C
authors.initials: C
authors.lastname: Pfleiderer