Field-induced spin level crossings within a quasi-XY antiferromagnetic state in Ba${}_2$FeSi${}_2$O${}_7$

Minseong Lee, Rico Schoenemann, Hao Zhang +11

We present a high-field study of the strongly anisotropic easy-plane square lattice $S$ = 2 quantum magnet Ba${}_2$FeSi${}_2$O${}_7$. This compound is a rare high-spin antiferromag…