Browse Prior Art Database

LOWER HC THROUGH SURFACE MODIFICATION

IP.com Disclosure Number: IPCOM000013010D
Original Publication Date: 2000-Apr-01
Included in the Prior Art Database: 2003-Jun-12

Publishing Venue

IBM

Abstract

A method is described to lower the coercivity of the spin valve freelayer structure. The method is to perform a light ion mill removal (~10A) of the oxide seed layer such as NiO or NiMnO prior to freelayer deposition. The new process reduces the freelayer coercivity from ~7 Oersteds to around 3 Oersteds for spin valve structures. Soft magnetic properties the of spin valve freelayer structures are critical for the performance of the spin valve heads. One of these parameters is the coercivity of the freelayer structure. Various seedlayer types are utilized to enhance the properties of the spin valve structures. One type of seedlayer is NiO, or NiMnO, which is typically 30A thick. It is observed that the coercivity of the freelayers deposited on these seedlayers are high when standard deposition steps are used. In the new method described here, an extra oxide seedlayer is deposited and this extra part (~10A) is then removed by ion milling which modifies the oxide surface. Then the remaining spin valve structure is deposited using the same processes and layers. The surface modification results in a large decrease in coercivity. Two spin valve structures; one processed using the standard method and the second one processed using the new method are listed below along with the dR/R and Hc values. dR/R and Hc of a spin valve structure deposited using standard process: NiMnO 30A dR/R 7% CoFe 7A Hc 7 Oe. NiFe 38A CoFe 15A Cu 24A CoFe 30A NiMn 250A Ta 50A