Fractional antiferro-skyrmion lattice in MnSc2S4 spinel

H. D. ROSALES; V. TSURKAN; S. GAO; F. A. GÓMEZ ALBARRACÍN; OKSANA ZAHARKO; G. KAUR; D. C. CABRA

La Plata

Workshop; Topology in Magnetism: Theory Meets Experiments; 2019

IFLYSIB, PSI

(contributed talk: Oksana Zaharko and Diego Rosales) MnSc2S4 spinel with magnetic Mn2+ ions forming the diamond lattice is an excellent model material for study magnetic frustration conceiving exotic states such as spiral spin liquid, competing long-range ordered phases and triple-q state in applied magnetic fields. Neutron diffuse scattering gives direct experimental evidence for the existence of the spiral spin liquid (TN1=2.3K0.125.Neutron single crystal diffraction unravels three long-range ordered phases supplanting each other on temperature lowering (TN1 =2.3K, q1 =(3/4 3/4 0);TN2 =1.75K, q2 =(3/4+d 3/4-d 0); TN3 =1.6K, q3 =q1 ) and, from the field variation of intensities of the different q3 arms discloses the triple-q state. In order to provide a better description of the magnetic behaviour we employ the Luttinger-Tisza approximation and extensive Monte Carlo simulations to scrutinize additional magnetic interactions. We propose a minimal model including the 3rd neighbor exchange coupling, single ion anisotropy and exchange anisotropy. With the inclusion of these ingredients we find good agreement between neutron scattering data and Monte Carlo simulations and establish that this set of parameters indeed stabilizes the lattice of dense topological objects akin to skyrmions