content_image/423423.jpg content_image/423426.jpg content_image/423422.jpg content_image/423425.jpg
A typical spin structure for the phase with (0, 0, 1) is described in Fig. 15. 

A typical spin structure for the phase with (1/2, 0, 1/2) is described in Fig. 16. 

## C. Helical ordered phase along the c axis; (0 , 0 , l ) 

The value l is obtained as l = 0 . 7023 for J$_{2}$ = − 1 . 68469 from Eq. (22). A typical spin structure is incommensu- rate with the lattice structure and described by Fig. 17. 

<img src='content_image/423423.jpg'>

<img src='content_image/423426.jpg'>

## A. Phase with ( h = 0 , k = 0 , l = 1) 

## B. Phase with ( h = 1 / 2 , k = 0 , l = 1 / 2) 

## D. Helical ordered phase along the c axis (Yoshimori); commensurate structure 

A typical spin structure with l = 0 . 71421 is commensu- rate with the lattice structure and described by Fig. 18. The magnetic unit cell along the c axis is seven times larger than the unit cell of the crystal unit cell. 

## E. Helical ordered phase along the a axis: ( h, 0 , 1) 

When J$_{3}$ = − 2 . 0 and J$_{1}$ = − 1, h is equal to 2/3 from Eq. 23). Then a typical spin structure is described by Fig. 19. 

<img src='content_image/423422.jpg'>

<img src='content_image/423425.jpg'>

