Magnetic anisotropy in single-crystal nickel films

Single-crystal films of nickel have been deposited in ultra high vacuum under closely controlled conditions, with a resulting high standard of lattice perfection as determined by electron microscopy. Anisotropy measurements made by torque magnetometry yielded the following conclusions:

1. K₁ has the same value as for bulk nickel (−5·0 × 10⁴erg cm⁻³ at room temperature). The magnetostrictive behaviour is predictable from bulk properties. An estimate of the order ofK₃ is also obtained (−3 × 10³ erg cm⁻³).

2. K_u can be reduced to extremely low levels by taking steps to exclude all known mechanisms.

3. The effect of stress on both K₁ and K_u have been investigated and correlated. A constraint temperature (about 110°C), well below the substrate temperature during deposition, has been established.

4. No contribution to K_u from mechanisms involving oxygen has been observed.

5. The effects of lattice imperfections are quite marked, and can be the predominant K_u source.