Nontrivial temperature dependence of magnetic anisotropy in multiferroics Ba${}_2$MnGe${}_2$O${}_7$

Shunsuke Hasegawa, Shohei Hayashida, Shinichiro Asai +3

We measured the temperature dependences of the static magnetization and the spin excitation in a square-lattice multiferroics Ba${}_2$MnGe${}_2$O${}_7$. An anisotropy gap of the observed…