Extremely Weakly Interacting ΔSz=0 and ΔSz=1 Excitations and Evidence for Fractional Quantization in a Magnetization Plateau: CeSb
| Autor: | Paul C. Canfield, Caiden Abel, Brinda Kuthanazhi, Arthur P. Ramirez, P. G. LaBarre |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Physical Review Letters. 125 |
| ISSN: | 1079-7114 0031-9007 |
| Popis: | The plateau at $1/3$ of the saturation magnetization ${M}_{s}$ in the metamagnet CeSb is accompanied by a state of ferromagnetic layers of spins in an up-up-down sequence. We measured $M$ and the specific heat $C$ in the plateau, spin wave analyses of which reveal two distinct branches of excitations. Those with $\mathrm{\ensuremath{\Delta}}{S}_{z}=1$ as measured by $M$, coexist with a much larger population of $\mathrm{\ensuremath{\Delta}}{S}_{z}=0$ excitations measured by $C$ but invisible to $M$. The large density of $\mathrm{\ensuremath{\Delta}}{S}_{z}=0$ excitations, their energy gap, and their seeming lack of interaction with $\mathrm{\ensuremath{\Delta}}{S}_{z}=1$ excitations suggest an analogy with astrophysical dark matter. Additionally, in the middle of the plateau three sharp jumps in $M(H)$ are seen, the size of which, $0.15%{M}_{s}$, is consistent with fractional quantization of magnetization per site in the down-spin layers. |
| Databáze: | OpenAIRE |
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