STRUCTURE AND MAGNETIC-PROPERTIES OF NI TI MULTILAYERS/

We report a study of structure and magnetic properties of Ni/Ti multil ayers with different modulation wavelength, 10 nm less than or equal t o lambda less than or equal to 40 nm, and constant sublayers thickness ratio d(Ni)/d(Ti) = 1. Specimens were characterized with X-ray diffra ction, vibrating sample magnetometer and torque meter in as-deposited state and in successive stages of isothermal annealing at 423 K. Hyste resis curves of as-deposited samples revealed the typical feature of f erromagnetic films with predominant shape anisotropy. During annealing very pronounced changes in the hysteresis loops were observed. An ana lysis of the loops indicates the occurrence of distinct changes in mag netic anisotropy of Ni sublayers: their effective shape anisotropy is drastically reduced due to a development of the perpendicular anisotro py and/or a modification of the microstructure. The effect can possibl y be applied to achieve desirable variation of perpendicular anisotrop y in multilayers which consist of Ni sublayers.