A substrate for a magnetic read/write head is disclosed. The substrate can reduce detachment of crystal grains when the substrate is machined. The substrate may be machined when the substrate is cut into strips or a flow path surface recess is formed to produce the magnetic read/write head. The reduced detachment of crystal grains makes the magnetic read/write head more resilient to chipping, which allows the magnetic read/write head to have a lower and more stable flying height that increases recording density.