On a surface of a bottom pole, a write gap film and first magnetic material film having a high saturation magnetic flux density are formed, and the first magnetic material film is etched to remain a portion extending from an air bearing surface to a throat height zero reference position and a first non-magnetic film is formed in a removed portion. The battery includes a first connector which is connected to a second connector of the electronic apparatus, the second connector being provided inside the opening. Feedback from one or more receivers may be used by a transmitter to improve quality, capacity, and scheduling in MIMO communication systems.