In this paper, we give a necessarly and sufficient condition for orbits of linear isotropy representations of Riemannian symmetric spaces are biharmonic submanifolds in hyperspheres in Euclidean spaces. In particular, we obtain examples of biharmonic submanifolds in hyperspheres whose co-dimension is greater than one.
"Biharmonic orbits of isotropy representations of symmetric spaces." Kodai Math. J. 42 (1) 48 - 63, March 2019. https://doi.org/10.2996/kmj/1552982505