FABRICATION AND CHARACTERIZATION OF MAGNETIC SUPERLATTICES - EPITAXIAL CO/CR(100) AND CO/CR(211) SUPERLATTICES

Epitaxial Co/Cr superlattices Co (1120)/Cr(100) on MgO (100) and Co(1100)/Cr(211) on MgO(110) have been grown by molecular beam epitaxy technique. Buffer layer of Mo or CrMo alloy was first deposited on top of the substrate which is crucial to prepare a smooth and well-ordered Cr surfaces and the following superlattices. The epitaxial orientation of Co/Cr (100) superlattices is Co[11 (2) over bar 0]//Cr[100]//MgO [100], Co[1 (1) over bar 00]//Cr[011]//MgO[010] and Co[0001]//Cr[01 (1) over bar]//MgO[001], while that for Co/Cr(211) is Co[1 (1) over bar 00]//Cr[211]//MgO[110], co[11 (2) over bar 0]//Cr[(1) over bar 11]//MgO[1 (1) over bar 0] and Co[0001]//Cr[01 (1) over bar]//MgO[001]. (Co(x)cr(y))(n) superlattices with different Co thickness (x), Cr thickness (y) and number of layers (n) have been deposited. The maximum magnetoresistance of the Co/Cr(211) superlattices is 18% comparing with the 4.8% for Co/Cr(100) superlattices. The magnetization measurements also show that the antiferromagnetic coupling in Co/Cr(211) superlattices is stronger than in Co/Cr(100) superlattices. The magnetic properties are strongly influenced by the crystal orientation of the multilayers.