Method of forming tunnel magnetoresistance (TMR) elements and TMR sensor element

A method includes performing an ion beam etching process on a tunnel magnetoresistance (TMR) stack to remove material portions of a first magnetic layer and a tunnel barrier layer of the TMR stack. The ion beam etching process stops at a top surface of a second magnetic layer of the TMR stack. A protective layer is deposited over the TMR stack. Another etch process is performed to remove the protective layer such that a portion of the second magnetic layer is exposed from the protective layer and a spacer is formed from a remaining portion of the protective layer. The spacer surrounds sidewalls of the first magnetic layer and the tunnel barrier layer. The portion of the second magnetic layer exposed from the protective layer is removed so that a TMR sensor element remains, where the TMR sensor element includes a bottom magnet, a top magnet, and a tunnel junction. 种方法包括对隧道磁阻(TMR)堆叠执行离子束蚀刻过程以移除所述TMR堆叠的第磁层和隧道势垒层的材料部分。所述离子束蚀刻过程在所述TMR堆叠的第二磁层的顶表面处停止。保护层沉积在所述TMR堆叠上方。另个蚀刻过程被执行以移除所述保护层，使得所述第二磁层的部分从所述保护层暴露并且由所述保护层的剩余部分