I can only recall this one, but however nowhere in the fluff is stated that Crozius have that "power". I'm no authority but I always thought that the "power field" is something that the object emits that separates/disrupts matter. The medium through which that is done can be varied because it's use is ultimately the "cut" from the field followed by the "blow" from the object that does the trick.
Although power fists seem to need to grip something, rather than punch, so I'm not even sure anymore. Understanding fictional game's mechanics was never my strong point
EDIT: I posted the image without a second look, other than that one there's only another I recall with a Chaplain:
though in retrospect none of them have crackling crozius, so I'll probably remove then later.