OSCILLATORY INTERLAYER COUPLING AND GIANT MAGNETORESISTANCE IN EPITAXIAL FE CR(211) AND (100) SUPERLATTICES/

An epitaxial orientation of Fe/Cr superlattices-Fe/Cr(211) on MgO(110) -is grown by magnetron sputtering. Its structural and magnetic charact erizations are presented and compared to those for Fe/Cr(100) superlat tices grown simultaneously onto MgO(100) substrates. The epitaxial ori entation of the Fe/Cr(211) superlattices is Fe/Cr[011BAR] parallel-to MgO[001] and Fe/Cr[111BAR] parallel-to MgO[110BAR], while that for Fe/ Cr(100) is Fe/Cr[00I] parallel-to MgO[0ll]. A uniaxial, in-plane surfa ce anisotropy for the Fe/Cr(211) superlattices along the Fe[011BAR] of 0.06 erg/cm2 is obtained from analysis of the magnetization hysteresi s loops. Four oscillations in the antiferromagnetic interlayer couplin g and giant magnetoresistance (GMR) are observed with a period of 18 a ngstrom for both orientations. The strength, oscillation period, and p hase of the magnetic coupling are identical for the two orientations. The GMR values increase by a factor of approximately 4 to 5 on cooling from room temperature to 4.2 K. At 4.2 K the maximum GMR value of the [Fe(14 angstrom)/Cr(8 angstrom)]50 superlattice is 70% for the (211) orientation and 150% for the (100) orientation.