Write head tester using inductance
AssigneeInfinitum Solutions, Inc.
InventorAlexander M. Taratorin
Life of this patent
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Abstract
A write head is tested by measuring the effect that magnetic fields have on the inductance of the write head. For example, a perpendicular write head may be placed in a magnetic field with a first angle, e.g., non-parallel and non-perpendicular, to the air bearing surface and the inductance is measured. After altering the angle of the magnetic field the inductance is again tested. In another embodiment, the angles may be parallel and perpendicular to the air bearing surface. The difference in the inductance value can be used to determine a characteristic of the write head, such as the presence of a recording pole. In some embodiments, the inductance may be measured while applying a bias current to the write head while the write head is in an external magnetic field.
Claims17
A method comprising:
- placing a write head in an external magnetic field that at least partially saturates the write head;
- applying a bias current to the write head to produce a magnetic field while the write head is in the external magnetic field;
- measuring the inductance of the write head while the write head produces the magnetic field and is in the external magnetic field;
- determining a characteristic of the write head based on the measured inductance of the write head;
- and
- recording the determined characteristic.
An apparatus for testing a write head, the apparatus comprising:
- a magnetic field generator that produces an external magnetic field that is applied to the write head to at least partially saturate the write head;
- a write circuit configured to be coupled to the write element to provide a bias current to the write element;
- an inductance meter configured to be coupled to the write head;
- and
- a processor coupled to the inductance meter and the magnetic field generator, the processor configured to receive an inductance measurement from the inductance meter while the write head is in the external magnetic field, the processor comprising a computer-usable medium having computer-readable program code embodied therein for causing the processor to control the bias current to the write head;
- to determine a characteristic of the write head based on an inductance measurement from the inductance meter taken while the bias current is provided to the write element and while the write head is in the external magnetic field;
- and to record the determined characteristic.
Dependencies are inferred from the claim text.