In order to have bash as your login on AIX, you have to change /etc/security/login.cfg:

default:
        sak_enabled = false
        logintimes =
        logindisable = 0
        logininterval = 0
        loginreenable = 0
        logindelay = 0




usw:
        shells = /bin/sh,/bin/bsh,/bin/csh,/bin/ksh,/bin/tsh,/bin/ksh93,/usr/bin/sh,/usr/bin/bsh,/usr/bin/csh,/usr/bin/ksh,/usr/bin/tsh,/usr/bin/ksh93,/usr/bin/rksh,/usr/bin/rksh93,/usr/sbin/uucp/uucico,/usr/sbin/sliplogin,/usr/sbin/snappd,/bin/bash
        maxlogins = 32767
        logintimeout = 60
        auth_type = STD_AUTH

Next:

chuser -a shell=/usr/bin/bash rigljoha