Patent ID: 8165709

Claim:
Lapping guides for use in fabrication of a magnetic recording head, comprising: a first differential electronic lapping guide (ELG) disposed in a first layer of the magnetic recording head, the first differential ELG having a first resistive element and a second resistive element between which is disposed a first common electrical lead; and a second differential ELG disposed in a second layer of the magnetic recording head, the second differential ELG having a third resistive element and a fourth resistive element between which is disposed a second common electrical lead, the second layer being different from the first layer; wherein the first and second differential ELGs share a common ground and a common current injection source distinct from the first common electrical lead and the second common electrical lead, and wherein remaining lapping distances at the first and second layers of the magnetic recording head are determined by measuring changing voltages across the first, second, third and fourth resistive elements, respectively.