The (100) Cu(100 Aring;)hyphen;Ni(25 Aring;) superlattice structure, grown on Cu/Si(100), that shows a reversed magnetic anisotropy between the inhyphen;plane and normalhyphen;tohyphen;plane magnetizations, has been heated to 400thinsp;deg;C, and the magnetic and structural changes investigated. The periodic structure remains mostly intact up to a 30hyphen;min heating at 300thinsp;deg;C, and partially so after heating at 400thinsp;deg;C. The reversed anisotropy, with a hysteresis loop seen for the field perpendicular to the film plane, but not for that parallel to the film plane, remains seen up to 400thinsp;deg;C. This is compared with two (100) Cu/Ni/Cu structures containing 50hyphen; and 500hyphen;Aring; Ni, respectively, with two 1000hyphen;Aring; Cu layers each. The former structure, with a completely reversed magnetic anisotropy, lost both the Ni layer and the magnetic characteristics after heating at 200thinsp;deg;C. The latter structure retained its magnetic properties up to 300thinsp;deg;C, and lost both the Ni layer and the magnetic characteristics after heating at 400thinsp;deg;C. The different reactions involved are discussed, including that with Si and mixing between Cu and Ni.
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