The role of interface impurities in Co/Cu giant magnetoresistance multilayers

Misfit dislocations in gold/Permalloy multilayers

“…The magnetotransport properties of these multilayers are sensitive to the composition of the multilayer system, the thickness of the individual layer, and the method (processing conditions) used for their synthesis. The dependence upon the process is thought to result from a sensitivity of the magnetic and electron transport properties to the crystal defect population trapped in the layers during their vapour-phase processing (Ranjan et al 1987, Nozie`res et al 1993, Nicholson et al 1994, Butler et al 1995, Wellock et al 1995. Ross et al (1996) have used high-resolution transmission electron microscopy (HRTEM) to examine the defect structure of a Ni 0.8 Fe 0.2 /Au/Ni 0.8 Fe 0.2 multilayer deposited by molecular-beam epitaxy.…”

Atomistic simulations of low energy ion assisted vapor deposition of metal multilayers

“…Many vapor deposition methods have been used to grow metal multilayers for GMR applications. [7][8][9][10][11] To achieve a high magnetoresistance, the thickness of both the magnetic and conducting layers must be small ͑typically around a few nanometers͒ and precisely controlled. [12][13][14][15][16] Both experimental 17 and recent theoretical 18 studies have also indicated that the magnetoresistance is a sensitive function of roughness and the degree of mixing at the metal interfaces.…”

Atomistic simulations of the vapor deposition of Ni/Cu/Ni multilayers: The effects of adatom incident energy

“…This giant magnetoresistive ͑GMR͒ effect was first discovered in Fe/Cr sandwiches in 1988, 1,2 but many material systems have since been found to exhibit the effect. Frequently studied examples include Co/Cu/Co, [7][8][9][10][11][12][13][14][15][16][17][18][19][20] NiFe͑Co͒/Cu/NiFe͑Co͒, [21][22][23][24] and NiCo/Cu/ NiCo systems. 25 The GMR effect is a result of spindependent electron scattering.…”

“…Although molecular beam epitaxy ͑MBE͒ techniques [8][9][10]24 have been used to successfully produce GMR multilayers, better films have been formed by a variety of sputter deposition methods. [3][4][5][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]32,33 The fundamental reasons for this are not yet established, but theoretical studies and numerous experiments have indicated that the GMR properties are sensitive to nanoscale structural features of the films, their defect populations and the intrinsic properties of the material system.…”

“…The GMR ratio therefore depends on nanoscale features of the multilayers such as the wavelength and amplitude of the interfacial roughness [3][4][5]7,11,32 and the width and extent of interfacial chemical mixing. 32 It may also be affected by grain texture, [10][11][12] composition, 18,21,25 layer purity, 9 and the various types of lattice defects ͑including vacancies, voids, dislocations, and twins͒ trapped in the films. 34 The nanostructural characteristics of deposited films that define GMR properties are sensitively affected by the choice of the deposition processes.…”