English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A significant number of Kondo-lattice ferromagnets order perpendicular to theeasy magnetization axis dictated by the crystalline electric field. The natureof this phenomenon has attracted considerable attention, but remains poorlyunderstood. In the present paper we use inelastic neutron scattering supportedby magnetization and specific heat measurements to study the spin dynamics inthe hard-axis ferromagnet CeAgSb2. In the zero field state we observed twosharp magnon modes, which are associated with Ce ordering and extended up to$\approx 3 meV with a considerable spin gap of 0.6 meV. Application of amagnetic field perpendicular to the moment direction reduces the spectralintensity and suppresses the gap and significantly enhances the low-temperaturespecific heat at a critical field of Bc ~ 2.8 T via a mean-field-liketransition. Above the transition, in the field polarized state, the gapeventually reopens due to the Zeeman effect. We modeled the observed dispersionusing linear spin-wave theory (LSWT) taking into account the ground state Gamma6 doublet and exchange anisotropy. Our model correctly captures the essentialfeatures of the spin dynamics including magnetic dispersion, distribution ofthe spectral intensity as well as the field-induced behavior, although severalminor features remain obscure. The observed spectra do not show significantbroadening due to the finite lifetime of the quasiparticles. Along with amoderate electronic specific heat coefficient gamma = 46 mJ/mol K2 thisindicates that the Kondo coupling is relatively weak and the Ce moments arewell localized. Altogether, our results provide profound insight into the spindynamics of the hard-axis ferromagnet CeAgSb2 and can be used as solid groundfor studying magnetic interactions in isostructural compounds includingCeAuSb2, which exhibits nematicity and unusual mesoscale magnetic textures.

Magnetic field-induced softening of spin waves and hard-axis order in Kondo-lattice ferromagnet CeAgSb$_{2}$